Fluctuation-induced conductivity analyses of Be-doped (BiCuLiTl)BaCaCuO superconductors in the critical regime and beyond
Nawazish A. Khan, Qurat-ul-Ain, Umber Firdous, and Shaheryar
We have successfully synthesized (BiCuLiTl)BaCaCuO and (BiCuLiTl)Ba(CaBe)CuO samples and studied their excess conductivity analyses (fluctuation-induced conductivity) of resistivity data. The main objective of such analyses is to investigate the influence of Be-substitution on the superconductivity ... [J. Appl. Phys. 111, 033917 (2012)] published Fri Feb 10, 2012.
Domain rotation induced strain effect on the magnetic and magneto-electric response in CoFeO/Pb(Mg,Nb)O-PbTiO heterostructures
Zhiguang Wang, Ravindranath Viswan, Bolin Hu, Jie-Fang Li, V. G. Harris et al.
The present work shows good control of both magnetic and electric properties with electric and magnetic fields, respectively, for epitaxial CoFeO (CFO) films on Pb(Mg,Nb)O-PbTiO (PMN-PT). X-ray reciprocal space mapping revealed a transformation between a- and c-domains in the PMN-PT under electric f ... [J. Appl. Phys. 111, 034108 (2012)] published Fri Feb 10, 2012.
Enhanced magnetic and electrical properties in amorphous Ge:Mn thin films by non-magnetic codoping
Wenjing Yin, Copeland D. Kell, Li He, Melissa C. Dolph, Chris Duska et al.
Amorphous GeMn thin films have been prepared by co-depositing Ge and Mn on SiO/Si using an ultrahigh vacuum molecular beam epitaxy system. Across a range of growth temperatures and Mn concentrations (2.8 at. %, 10.9 at. %, and 21.3 at. %), we achieved enhanced magnetic and electrical properties with ... [J. Appl. Phys. 111, 033916 (2012)] published Fri Feb 10, 2012.
Enhancing and broadening absorption properties of frequency selective surfaces absorbers using FeCoB-based thin film
Wenyi Ren, Yan Nie, Xuan Xiong, Cui Zhang, Yan Zhou et al.
In this paper, the influence of FeCoB-based magnetic film on the absorption properties of traditional frequency selective surface (FSS) was investigated experimentally. A single-layer Minkowski fractal planar frequency selective surface was chosen, and the laser etching technique was proposed to fab ... [J. Appl. Phys. 111, 07E703 (2012)] published Fri Feb 10, 2012.
Effects of substrate on structure and the magnetic properties of (001)-textured FePt films grown at low temperature
A. M. Zhang, Z. X. Chen, W. Q. Zou, B. Lv, J. J. Ge et al.
(001)-oriented FePt films are deposited, by magnetron sputtering at 300 degrees C, on LaAlO (001), SrTiO (001), and MgO (001) single crystal substrates. The tetragonal distortion, magnetic anisotropy, and the coercive force of the films vary with the substrate. The ordering process is very differen ... [J. Appl. Phys. 111, 07A704 (2012)] published Fri Feb 10, 2012.
Large magnetocaloric effect for magnetic refrigeration from 210 to ~275 K in LaCaMnCoO
Y. D. Zhang, The-Long Phan, and S. C. Yu
We have studied the magnetic properties and magnetocaloric effect in LaCaMnCoO (x = 00.05) prepared by conventional solid-state reaction. Magnetic measurements versus temperature revealed that both magnetization and the Curie temperature (T) decreased gradually with increasing Co content (x); T valu ... [J. Appl. Phys. 111, 07D703 (2012)] published Fri Feb 10, 2012.
E-field tuning microwave frequency performance of CoFeSi/lead zinc niobatelead titanate magnetoelectric coupling composites
Shandong Li, Ming Liu, J. Lou, Shawn Beguhn, Jianpeng Wu et al.
Nanocrystalline CoFeSi Heusler alloy films were deposited on single crystal lead zinc niobatelead titanate substrates. It is revealed that this multiferroic composite exhibits very strong continuously electric field (E-field) tunable microwave frequency characteristics. With an increase of the E-fie ... [J. Appl. Phys. 111, 07C705 (2012)] published Fri Feb 10, 2012.
Effect of deviation from stoichiometric composition on structural and magnetic properties of cobalt ferrite, CoFeO (x = 0.2 to 1.0)
I. C. Nlebedim, J. E. Snyder, A. J. Moses, and D. C. Jiles
The effects of deviation from stoichiometric composition on the structural and magnetic properties of cobalt ferrite, CoFeO (x = 0.2 to 1.0), are presented. Both CoFeO and FeO have a spinel crystal structure, and it might be expected that intermediate compositions would have the same structure. Howe ... [J. Appl. Phys. 111, 07D704 (2012)] published Fri Feb 10, 2012.
Controlling the core-to-core distance of vortex pairs in exchange-biased iron elliptical nanoelements
Felipe F. Oliveira, Thiago R. S. Moura, A. S. Carrico, Ana L. Dantas, and G. O. G. Reboucas
We report a theoretical study of vortex pairs in exchange-biased elliptical iron nanoelements. We show that the remanent state may be tailored to fit vortex pairs with opposite chiralities separated by a diamond-like domain. Flat nanoelements with lateral dimensions ranging from 115 nm x 425 nm to ... [J. Appl. Phys. 111, 07D102 (2012)] published Fri Feb 10, 2012.
Magnetocaloric materials with first-order phase transition: thermal and magnetic hysteresis in LaFeSi and NiMnGa (invited)
K. P. Skokov, V. V. Khovaylo, K.-H. Muller, J. D. Moore, J. Liu et al.
This is a report on a comparative study of thermal and magnetic hysteresis in LaFeSi and NiMnGa polycrystalline samples near their first-order phase transitions by measurements of magnetization and direct measurements of the adiabatic temperature change, DeltaT(H). Based on the obtained M(T) and M(H ... [J. Appl. Phys. 111, 07A910 (2012)] published Fri Feb 10, 2012.
Volume exchange in soft FeCo films of high magnetization
Christoph Mathieu, Hau-Jian Liu, Kristen S. Buchanan, and Venkateswara R. Inturi
Soft FeCo films of high magnetization are a well known integral part of today's magnetic recording heads. Values for the volume exchange, an important parameter since it determines exchange length, domain wall width, and energy are, however, available for few compositions of FeCo in spite of the wid ... [J. Appl. Phys. 111, 07A306 (2012)] published Fri Feb 10, 2012.
Bulk nanocomposite using self-forming core/shell nanoparticles and its magnetic properties for high-frequency applications
Tomohiro Suetsuna, Koichi Harada, Toshihide Takahashi, and Seiichi Suenaga
A bulk nanocomposite composed of tightly packed self-forming core/shell nanoparticles of metal/oxide was fabricated. The crystalline grain size of the nanoparticles, the packing ratio, and the composition were controlled in the nanocomposite, and their effects on the magnetic properties were investi ... [J. Appl. Phys. 111, 07A307 (2012)] published Fri Feb 10, 2012.
Charge density waves condensate as measure of charge order and disorder in EuSrMnO (x = 0.50, 0.58) manganites
Parul Pandey, Nilesh Awari, Rakesh Rana, Abhishek Singh, S. S. Prabhu et al.
We have explored the low-energy excitations in epitaxial thin films of EuSrMnO [x = 0.50: spin-glass with short range charge-order and x = 0.58: long range charge-order] using terahertz time-domain spectroscopy. A finite frequency peak structure in optical conductivity is observed at ~3.5 meV for bo ... [Appl. Phys. Lett. 100, 062408 (2012)] published Fri Feb 10, 2012.
Tantalum nitride superconducting single-photon detectors with low cut-off energy
A. Engel, A. Aeschbacher, K. Inderbitzin, A. Schilling, K. Il'in et al.
Materials with a small superconducting energy gap are expected to favor a high detection efficiency of low-energy photons in superconducting nanowire single-photon detectors. We developed a TaN detector with smaller gap and lower density of states at the Fermi energy than in comparable NbN devices, ... [Appl. Phys. Lett. 100, 062601 (2012)] published Fri Feb 10, 2012.
First-principles characterization of ferromagnetism in N-doped SrTiO and BaTiO
Kesong Yang, Ying Dai, and Baibiao Huang
The spin-polarization and magnetic coupling character of N-doped SrTiO (STO) and BaTiO (BTO) are studied through first-principles calculations. The substitutional N doping at O sites leads to a half-metallic property and produces a magnetic moment of 1.0 [mu]. The magnetic interaction between the ne ... [Appl. Phys. Lett. 100, 062409 (2012)] published Fri Feb 10, 2012.
Formation and structure of 360 and 540 degree domain walls in thin magnetic stripes
Youngman Jang, S. R. Bowden, Mark Mascaro, J. Unguris, and C. A. Ross
360 degrees , 540 degrees , and other complex transverse domain walls have been created in narrow cobalt wires connected to injection pads by cycling a magnetic field perpendicular to the wire length. The composite walls, formed by impingement of 180 degrees transverse walls of alternating chiralit ... [Appl. Phys. Lett. 100, 062407 (2012)] published Fri Feb 10, 2012.
Electronic and magnetic properties of LaNiMnO and LaCoMnO with cationic ordering
Min Zhu, Yong Lin, Edward W. C. Lo, Qiong Wang, Zhengjie Zhao et al.
Employing first-principles electronic structure calculations, the electronic and magnetic properties of LaNiMnO and LaCoMnO with Ni/Mn and Co/Mn ordering in (001), (110), and (111) directions are investigated. The ground states of LaNiMnO and LaCoMnO are ferromagnetic semiconducting with alternative ... [Appl. Phys. Lett. 100, 062406 (2012)] published Fri Feb 10, 2012.
Direct Observation of Unconventional Topological Spin Structure in Coupled Magnetic Discs
C. Phatak, A. K. Petford-Long, and O. Heinonen
Confined magnetic thin films are known to exhibit a variety of fascinating topological spin states such as Skyrmions, vortices, and antivortices. Such topological excitations are fundamentally important to our understanding of quantum critical phenomenon and related phase transitions. Here we report ... [Phys. Rev. Lett. 108, 067205 ] published .
Quantum Ice: A Quantum Monte Carlo Study
Nic Shannon, Olga Sikora, Frank Pollmann, Karlo Penc, and Peter Fulde
Ice states, in which frustrated interactions lead to a macroscopic ground-state degeneracy, occur in water ice, in problems of frustrated charge order on the pyrochlore lattice, and in the family of rare-earth magnets collectively known as spin ice. Of particular interest at the moment are quantum s ... [Phys. Rev. Lett. 108, 067204 ] published .
Magnetotransport at Domain Walls in BiFeO
Q. He, C.-H. Yeh, J.-C. Yang, G. Singh-Bhalla, C.-W. Liang et al.
Domain walls in multiferroics can exhibit intriguing behaviors that are significantly different from the bulk of the material. We investigate strong magnetoresistance in domain walls of the model multiferroic BiFeO by probing ordered arrays of 109 degrees domain walls with temperature- and magnetic ... [Phys. Rev. Lett. 108, 067203 ] published .
Magnetic properties of the doped spin-(1/2) honeycomb-lattice compound InCuVO
Y. J. Yan, Z. Y. Li, T. Zhang, X. G. Luo, G. J. Ye et al.
We report magnetic properties in the Co- and Zn-doped spin-1/2 honeycomb-lattice compound InCuVO. Magnetic susceptibility and specific heat experiments show no long-range ordering down to 2 K in InCuVO. Analyses of electronic structures and states suggest that the ground state of undoped InCuVO is p ... [Phys. Rev. B 85, 085102 ] published .
Reconstructing the bulk Fermi surface and superconducting gap properties from neutron scattering experiments
Tanmoy Das, R. S. Markiewicz, and A. Bansil
We develop an analytical tool to extract bulk electronic properties of unconventional superconductors from inelastic neutron scattering spectra. We show that the upward and downward branches of the spin excitation spectra have distinct origins, with the upper branch representing a gapped spin-wave d ... [Phys. Rev. B 85, 064510 ] published .
Magnetic-field tuned anisotropy in superconducting RbFeSe
S. Bosma, R. Puzniak, A. Krzton-Maziopa, M. Bendele, E. Pomjakushina et al.
The anisotropic superconducting properties of a RbFeSe single crystal with T~=32 K were investigated by means of superconducting quantum interference device (SQUID) and torque magnetometry, probing the effective magnetic penetration depth lambda and the magnetic penetration depth anisotropy gamma. I ... [Phys. Rev. B 85, 064509 ] published .
Phase transitions in spin-orbital models with spin-space anisotropies for iron pnictides: Monte Carlo simulations
Ryan Applegate, Rajiv R. P. Singh, Cheng-Chien Chen, and Thomas P. Devereaux
The common phase diagrams of superconducting iron pnictides show interesting material specificities in the structural and magnetic phase transitions. In some cases the two transitions are separate and second order, while in others they appear to happen concomitantly as a single first-order transitio ... [Phys. Rev. B 85, 054411 ] published .
Enhancement of ferromagnetism in Ni excess CuNiMnSb half Heusler alloys
B. L. Ahuja, Alpa Dashora, Shailja Tiwari, H. S. Mund, Madhumita Halder et al.
Spin momentum densities of CuNiMnSb (for x = 0.17 and 0.22), derived from experimental magnetic Compton profiles (MCPs), show an increase in magnetic moment while going from x = 0.17 --> 0.22, which is attributed to Mn 3d states. MCPs along with magnetization data suggest a negligible contribution o ... [J. Appl. Phys. 111, 033914 (2012)] published Thu Feb 9, 2012.
Angular and frequency dependence of standing spin waves in FePt films
D. M. Jacobi, E. Sallica Leva, N. Alvarez, M. Vasquez Mansilla, J. Gomez et al.
We present a detailed analysis of the dynamic response of the magnetization in as-made FePt thin films, particularly studying the angular dependence of standing spin waves that can be observed when the external field is applied close to the film normal. We have found that the field separation betwee ... [J. Appl. Phys. 111, 033911 (2012)] published Thu Feb 9, 2012.
Imaging of magnetic flux distribution in vicinity of insulating particles in high-T superconductor by electron holography
Zentaro Akase, Hiroto Kasai, Shuichi Mamishin, Daisuke Shindo, Mitsuru Morita et al.
REBaCuO (RE: rare earth) bulk superconductors, whose microstructures can be controlled by quench and melt growth (QMG) processing, have a high critical current density J, which makes them well suited for use in practical applications. Through a combination of electron holography and a focused ion-be ... [J. Appl. Phys. 111, 033912 (2012)] published Thu Feb 9, 2012.
A magnetoelectric multiglass state in multiferroic YbFeO
Y. Sun, Y. Liu, F. Ye, S. Chi, Y. Ren et al.
A multiglass state in which two distinct glassy phases coexist has been identified in multiferroic YbFeO. A collective magnetic freezing, as evidenced by AC susceptibility, magnetization, and coercivity measurements, develops at a freezing temperature T ~ 80 K. Meanwhile, the low-temperature dielect ... [J. Appl. Phys. 111, 07D902 (2012)] published Thu Feb 9, 2012.
Magnetic transitions in erbium at high pressures
Sarah A. Thomas, Georgiy M. Tsoi, Lowell E. Wenger, Yogesh K. Vohra, and Samuel T. Weir
Electrical resistance measurements have been carried out on polycrystalline erbium (Er) at temperatures down to 10 K and pressures up to 20 GPa. An abrupt change in the slope of the resistance is observed with decreasing temperature below 84 K which is associated with the c-axis modulated antiferrom ... [J. Appl. Phys. 111, 07E104 (2012)] published Thu Feb 9, 2012.
Reduction of hysteresis loss and large magnetocaloric effect in the C- and H-doped La(Fe, Si) compounds around room temperature
H. Zhang, B. G. Shen, Z. Y. Xu, X. Q. Zheng, J. Shen et al.
The effects of the interstitial C and H atoms on the phase formation, the hysteresis loss, and magnetocaloric effects of the NaZn-type La(Fe, Si) compounds are investigated. It is found that the annealing time to obtain a 1:13 structure is significantly reduced from 40 days for LaFeSi to a week for ... [J. Appl. Phys. 111, 07A909 (2012)] published Thu Feb 9, 2012.
Room temperature ferromagnetism in monoclinic Mn-doped ZrO thin films
Nguyen Hoa Hong, C.-K. Park, A. T. Raghavender, O. Ciftja, N. S. Bingham et al.
Theory has predicted that high temperature ferromagnetism (FM) should be found in cubic Mn-doped ZrO. Our experimental data reveal room temperature FM in Mn-doped ZrO thin films grown on LaAlO substrates. The largest saturated magnetic moment (M) is found to be about 13.8 [mu]/Mn for the cubic MnZrO ... [J. Appl. Phys. 111, 07C302 (2012)] published Thu Feb 9, 2012.
Surface morphologies and magnetic properties of Fe and Co magnetic thin films on polyethylene naphthalate organic substrates
Hideo Kaiju, Taro Abe, Kenji Kondo, and Akira Ishibashi
We have studied the surface morphologies and magnetic properties of Fe and Co thin films evaporated on polyethylene naphthalate (PEN) organic substrates toward the fabrication of spin quantum cross devices. As a result, the surface roughnesses of Co (6.1 nm)/PEN and Co (12 nm)/PEN are as small as 0. ... [J. Appl. Phys. 111, 07C104 (2012)] published Thu Feb 9, 2012.
Co/Pt multilayer-based magnetic tunnel junctions with perpendicular magnetic anisotropy
Zoe Kugler, Jan-Philipp Grote, Volker Drewello, Oliver Schebaum, Gunter Reiss et al.
Temperature-dependent transport measurements of magnetic tunnel junctions with perpendicularly magnetized Co/Pt electrodes are presented. Magnetization measurements of the Co/Pt multilayers are performed to characterize the electrodes. The interface magnetization of the Co layers at the Pt interface ... [J. Appl. Phys. 111, 07C703 (2012)] published Thu Feb 9, 2012.
Tuning of magnetization dynamics in sputtered CoFeB thin film by gas pressure
Feng Xu, Qijun Huang, Zhiqin Liao, Shandong Li, and C. K. Ong
The influences of sputtering gas pressure on the high-frequency magnetization dynamics of as-sputtered CoFeB thin films are studied with permeability spectra based on the Landau-Lifshitz-Gilbert (LLG) equation. Results show that with the pressure increasing, both the anisotropy field and resonance f ... [J. Appl. Phys. 111, 07A304 (2012)] published Thu Feb 9, 2012.
Magnetocaloric effect in LaPrFeSi compounds with a combined addition of Co and C
Jun Shen and Jin-Liang Zhao
The influence of a combined addition of Co and C on the magnetocaloric effect in the LaPrFeSi compound is investigated. The addition of Co and C can adjust Curie temperature (T) to around room temperature. Although the magnetic entropy change (DeltaS) of LaPrFeCoSiC decreases with the increase of x, ... [J. Appl. Phys. 111, 07A908 (2012)] published Thu Feb 9, 2012.
Variational Numerical Renormalization Group: Bridging the Gap between NRG and Density Matrix Renormalization Group
Iztok Pizorn and Frank Verstraete
The numerical renormalization group (NRG) is rephrased as a variational method with the cost function given by the sum of all the energies of the effective low-energy Hamiltonian. This allows us to systematically improve the spectrum obtained by NRG through sweeping. The ensuing algorithm has a lot ... [Phys. Rev. Lett. 108, 067202 ] published .
Quantum Order-by-Disorder Near Criticality and the Secret of Partial Order in MnSi
Frank Kruger, Una Karahasanovic, and Andrew G. Green
The vicinity of quantum phase transitions has proven fertile ground in the search for new quantum phases. We propose a physically motivated and unifying description of phase reconstruction near metallic quantum-critical points using the idea of quantum order by disorder. Certain deformations of the ... [Phys. Rev. Lett. 108, 067003 ] published .
Manifestly Non-Gaussian Fluctuations in Superconductor-Normal Metal Tunnel Nanostructures
M. A. Laakso, T. T. Heikkila, and Yuli V. Nazarov
We propose a mesoscopic setup which exhibits strong and manifestly non-Gaussian fluctuations of energy and temperature when suitably driven out of equilibrium. The setup consists of a normal metal island (N) coupled by tunnel junctions (I) to two superconducting leads (S), forming a SINIS structure, ... [Phys. Rev. Lett. 108, 067002 ] published .
Avoidance of Majorana Resonances in Periodic Topological Superconductor-Nanowire Structures
Jay D. Sau, Chien Hung Lin, Hoi-Yin Hui, and S. Das Sarma
Semiconducting nanowires in proximity to superconductors are promising experimental systems for Majorana fermions which may ultimately be used as building blocks for topological quantum computers. A serious challenge in the experimental realization of the Majorana fermion in these semiconductor-supe ... [Phys. Rev. Lett. 108, 067001 ] published .
Velocity-induced reorientation of a fast driven Abrikosov lattice
S. Okuma, D. Shimamoto, and N. Kokubo
From mode-locking measurements where the vortex lattice is driven quickly by superimposed dc and ac currents, we find a velocity-induced rotation of lattice orientation from a perpendicular to a parallel orientation. This is a dynamic transition caused by increased velocity. At the threshold of the ... [Phys. Rev. B 85, 064508 ] published .
Ground-state phase diagram of the quantum JJ model on the honeycomb lattice
Fabio Mezzacapo and Massimo Boninsegni
We study the ground-state phase diagram of the quantum JJ model on the honeycomb lattice by means of an entangled-plaquette variational ansatz. Values of energy and relevant order parameters are computed in the range 0<=J/J<=1. The system displays classical order for J/J<~0.2 (Neel) and for J/J>~0.4 ... [Phys. Rev. B 85, 060402 ] published .
Synthesis, microstructure and magnetic properties of low Nd content FeNdBM (M = Hf, Ti and Ta) alloys
Zeqiang Zhang, Parmanand Sharma, Kunio Yubuta, and Akihiro Makino
We have investigated the effects of Hf, Ti and Ta addition on crystallization behavior, microstructure and magnetic properties of melt-spun FeNdBM (M = Hf, Ti and Ta) alloy ribbons. Optimization of processing conditions lead to the development of nano-composite magnets, made from high B soft magneti ... [J. Appl. Phys. 111, 07B501 (2012)] published Wed Feb 8, 2012.
Condition of the ratchet effect of a magnetic domain wall motion under an asymmetric potential energy
Hong-Guang Piao, Xiaozhong Zhang, Hyeok-Cheol Choi, Dong-Hyun Kim, and Chun-Yeol You
We have investigated the ratchet effect of magnetic domain wall (DW) motion in a straight ferromagnetic nanowire under ac magnetic field by means of micromagnetic simulation. A structure-stable DW ratchet effect along the ferromagnetic nanowire is observed utilizing an asymmetric potential produced ... [J. Appl. Phys. 111, 07D301 (2012)] published Wed Feb 8, 2012.
Spin reorientation transition and hard magnetic properties of MnBi intermetallic compound
K. Suzuki, X. Wu, V. Ly, T. Shoji, A. Kato et al.
The effects of mechanical grinding (MG) on the crystallite size, the spin reorientation transition temperature (T) and the hard magnetic properties in melt-spun low temperature phase (LTP) MnBi have been investigated in order to understand the origin of magnetic hardening induced by MG. The room-tem ... [J. Appl. Phys. 111, 07E303 (2012)] published Wed Feb 8, 2012.
Random magnetization dynamics at elevated temperatures
I. Mayergoyz, G. Bertotti, C. Serpico, Z. Liu, and A. Lee
Generalization of the classical Landau-Lifshitz equation for the case of magnetization dynamics at elevated temperatures is discussed. This generalization is based on the description of thermal bath effects by a jump-noise process, and it results in equations that describe magnetization dynamics whe ... [J. Appl. Phys. 111, 07D501 (2012)] published Wed Feb 8, 2012.
Non-collinear magnetic profile in (Rh/FeCo)/Rh(001) bilayer probed by polarized soft x-ray resonant magnetic reflectivity
M. Przybylski, J.-M. Tonnerre, F. Yildiz, H. C. N. Tolentino, and J. Kirschner
Magnetization configuration in Fe/Rh/FeCo/Rh(001) can be non-orthogonal due to competition between the anisotropy and the exchange coupling. Soft x-ray resonant magnetic reflectivity allows us to probe the magnetic profile along the growth axis with in-plane and perpendicular magnetization component ... [J. Appl. Phys. 111, 07C103 (2012)] published Wed Feb 8, 2012.
Electronic and magnetic properties of substitutionally Fe-, Co-, and Ni-doped BC honeycomb structure
Xianqing Lin and Jun Ni
First-principles calculations have been performed to investigate the electronic and magnetic properties of BC honeycomb structure (2D BC) substitutionally doped with Fe, Co, and Ni. 2D BC is a semiconductor with a mediate bandgap. When substituting for B, the Fe, Co, and Ni impurity atoms exhibit di ... [J. Appl. Phys. 111, 034309 (2012)] published Wed Feb 8, 2012.
Ab initio investigations of phonons and superconductivity in the cubic Laves structures LaAl and YAl
S. Duman and H. M. Tutuncu
We have performed an ab initio study of structural, elastic, electronic, lattice-dynamical, and electron-phonon interaction properties of the cubic Laves structures LaAl and YAl. The calculations have been carried out within the density-functional theory and linear response formalism using pseudopot ... [J. Appl. Phys. 111, 033514 (2012)] published Wed Feb 8, 2012.
Asymmetric switching behavior in perpendicularly magnetized spin-valve nanopillars due to the polarizer dipole field
D. B. Gopman, D. Bedau, S. Mangin, C. H. Lambert, E. E. Fullerton et al.
We report the free layer switching field distributions of spin-valve nanopillars with perpendicular magnetization. While the distributions are consistent with a thermal activation model, they show a strong asymmetry between the parallel to antiparallel and the reverse transition, with energy barrier ... [Appl. Phys. Lett. 100, 062404 (2012)] published Wed Feb 8, 2012.
Semiclassical theory of magnetoresistance in positionally disordered organic semiconductors
N. J. Harmon and M. E. Flatte
A recently introduced percolative theory of unipolar organic magnetoresistance is generalized by treating the hyperfine interaction semiclassically for an arbitrary hopping rate. Compact analytic results for the magnetoresistance are achievable when carrier hopping occurs much more frequently than t ... [Phys. Rev. B 85, 075204 ] published .
Magnetic field dependence of the quantum tunneling of normal-superconductor interfaces in a type-I Pb superconductor
Saul Velez, Ricardo Zarzuela, Antoni Garcia-Santiago, and Javier Tejada
We report experimental evidence of the effect of an applied magnetic field on the nonthermal magnetic relaxation in a disk-shaped type-I lead superconductor. The time evolution of the irreversible magnetization proves to be logarithmic for a wide range of temperatures and magnetic field values along ... [Phys. Rev. B 85, 064506 ] published .
Domain structure and magnetic pinning in ferromagnetic/superconducting hybrids
V. Vlasko-Vlasov, A. Buzdin, A. Melnikov, U. Welp, D. Rosenmann et al.
Magnetic patterns in three iron-garnet films with different magnetic properties covered with 100-nm superconducting Nb film are studied using a magneto-optical imaging technique. In all samples the strong coupling between ferromagnetic domains and vortices noticeably modifies the magnetization proce ... [Phys. Rev. B 85, 064505 ] published .
Effects of magnetic field, anisotropy, and biquadratic interactions in type-IIA fcc antiferromagnets studied by linear spin-wave theory
Trinanjan Datta and Dao-Xin Yao
We study the spin dynamics in a 3D quantum antiferromagnet on a face-centered-cubic (fcc) lattice. The effects of magnetic field, single-ion anisotropy, and biquadratic interactions are investigated using linear spin-wave theory with spins in a canted basis about the type-IIA fcc antiferromagnetic g ... [Phys. Rev. B 85, 054409 ] published .
Critical temperature and correlation length of an elastic interaction model for spin-crossover materials
Taro Nakada, Takashi Mori, Seiji Miyashita, Masamichi Nishino, Synge Todo et al.
It has previously been pointed out that the coexistence of infinite-range and short-range interactions causes a system to have a phase transition of the mean-field universality class, in which the cluster size is finite even at the critical point. In the present paper, we study this property in a mo ... [Phys. Rev. B 85, 054408 ] published .
First-principles study of structural, magnetic, and electronic properties of small Fe-Rh alloy clusters
Junais Habeeb Mokkath and G. M. Pastor
The structural, electronic, and magnetic properties of small FeRh clusters having N=m+n<=8 atoms are studied in the framework of a generalized-gradient approximation to density-functional theory. For N=m+n<=6, a thorough sampling of all cluster topologies has been performed, while for N=7 and 8, onl ... [Phys. Rev. B 85, 054407 ] published .
Suppression of edge magnetism in a titanium-embedded zigzag graphene nanoribbon
Yu Guodong, Lu Xiaoling, Zheng Yisong, and Tian Wenjing
Electronic and magnetic properties of zigzag-edged graphene nanoribbons (ZGNR) embedded with titanium (Ti) atoms are studied by means of the first principle calculations. When Ti atoms are positioned near either edge of the ZGNR, the magnetic moment at this edge is rapidly suppressed as the Ti conce ... [J. Appl. Phys. 111, 033707 (2012)] published Tue Feb 7, 2012.
Thickness-dependent evolution of magnetization reversal in micron-scale polycrystalline Fe rings
Yu-feng Hou and Kannan M. Krishnan
The evolution of magnetic switching mechanism is investigated for micron-scale polycrystalline Fe ring arrays with Fe layer thickness, t, varying between 10 nm and 50 nm. Single-step and double-step switching are observed for the 10 nm and 50 nm rings, with the 30 nm sample showing a transient behav ... [J. Appl. Phys. 111, 033910 (2012)] published Tue Feb 7, 2012.
Emergent magnetic monopoles, disorder, and avalanches in artificial kagome spin ice (invited)
R. V. Hugli, G. Duff, B. O'Conchuir, E. Mengotti, L. J. Heyderman et al.
We study artificial spin ice with isolated elongated nanoscale islands arranged in a kagome lattice and solely interacting via long range dipolar fields. The artificial kagome spin ice displays a phenomenology similar to the microscopic pyrochlore system, where excitations at sub-Kelvin temperatures ... [J. Appl. Phys. 111, 07E103 (2012)] published Tue Feb 7, 2012.
Electron resonance and magnetic response of low-doped LaCaMnO and LaSrMnO manganite single crystals
E. Rozenberg, A. I. Shames, M. I. Tsindlekht, I. Felner, and Ya. M. Mukovskii
Ferromagnetic resonance and ac/dc magnetic properties of the low-doped LaCaMnO and LaSrMnO manganite single crystals were studied below (down to 5 K) their paramagnetic-ferromagnetic phase transition. It appears that technologically driven chemical/structural disorder inherent to low-doped manganite ... [J. Appl. Phys. 111, 07D702 (2012)] published Tue Feb 7, 2012.
Scaling fit of spin pumping in various ferromagnetic materials
T. Yoshino, K. Ando, Y. Kajiwara, H. Nakayama, and E. Saitoh
In this paper, we have investigated spin currents generated by the spin pumping in ferromagnetic metal/Pt and ferromagnetic insulator/Pt bilayer films using the inverse spin-Hall effect (ISHE). We found that the magnitude of the electric voltage due to the ISHE is well reproduced by a calculation ba ... [J. Appl. Phys. 111, 07C502 (2012)] published Tue Feb 7, 2012.
1s2p resonant inelastic x-ray scattering-magnetic circular dichroism: A sensitive probe of 3d magnetic moments using hard x-ray photons
M. Sikora, A. Juhin, G. Simon, M. Zajac, K. Biernacka et al.
We investigated the magnetic properties of thin magnetite and iron films grown on MgO(001) by means of hard x-ray photon-in photon-out probe, namely, 1s2p resonant inelastic x-ray scattering-magnetic circular dichroism (RIXS-MCD). A comparison of the spectra acquired from bulk and thin layer magneti ... [J. Appl. Phys. 111, 07E301 (2012)] published Tue Feb 7, 2012.
The compressive stress effect on the magnetostriction and magnetization for Sm-Dy-Fe composites
Bowen Wang, Zhihua Wang, Yanming Hao, Ling Weng, Wenmei Huang et al.
SmDyFe rod composites were fabricated under a compaction pressure of 800 MPa along the rod direction and in a magnetic field of 200 kA/m along the direction, perpendicular to the rod axis. It is found that the magnetostriction lambda parallel to the rod direction is almost unchanged with increasing ... [J. Appl. Phys. 111, 07A906 (2012)] published Tue Feb 7, 2012.
Oscillatory magnetic anisotropy due to quantum well states in thin ferromagnetic films (invited)
M. Przybylski, M. Dabrowski, U. Bauer, M. Cinal, and J. Kirschner
Magnetic anisotropy depends strongly on the density of states at the Fermi level. If significant contributions to magnetocrystalline anisotropy energy (MAE) are due to spin-polarized quantum well states (QWS), a significant increase of MAE can occur periodically as a function of film thickness. The ... [J. Appl. Phys. 111, 07C102 (2012)] published Tue Feb 7, 2012.
Domain structure and magnetization loss in a toroidal core based on an Fe-based amorphous alloy
Daichi Azuma, Ryusuke Hasegawa, Shin Saito, and Migaku Takahashi
By utilizing a wide-view Kerr-effect magnetic domain observation system designed for domain observation on curved surfaces, domain images were taken on the surface of a toroidal core based on an Fe-based amorphous alloy. The results of the observation are discussed in terms of Bertotti's eddy-curren ... [J. Appl. Phys. 111, 07A302 (2012)] published Tue Feb 7, 2012.
Magnetic characteristics of a new cubic defect spinel LiMgMnO
V. Singh, M. S. Seehra, A. Manivannan, and P. N. Kumta
Magnetic properties of LiMgMnO nanoparticles (size ~= 20 nm) synthesized by the Pechini method are investigated using temperature dependence of its magnetization (M) and electron magnetic resonance (EMR) spectra at 9.286 GHz. Analysis of the x-ray diffraction spectra yields its structure to be a cub ... [J. Appl. Phys. 111, 07E302 (2012)] published Tue Feb 7, 2012.
Behavior of magnetic fieldannealed Galfenol steel
Michael Brooks, Eric Summers, J. B. Restorff, and M. Wun-Fogle
An attractive feature of the Galfenol alloy system is the ability to impart enough uniaxial anisotropy into the alloy such that no pre-load mechanism is required to attain saturation magnetostriction. Stress annealing is typically employed to generate this anisotropy. Recent published results indica ... [J. Appl. Phys. 111, 07A907 (2012)] published Tue Feb 7, 2012.
Broadband ferromagnetic resonance spectroscopy of permalloy triangular nanorings
J. Ding, M. Kostylev, and A. O. Adeyeye
We investigate the spin dynamics in triangular shaped permalloy rings using broadband ferromagnetic resonance spectroscopy. Compared with circular rings, we observed multiple resonance frequency peaks, which are strongly dependent on the orientation of the applied magnetic field relative to the hori ... [Appl. Phys. Lett. 100, 062401 (2012)] published Tue Feb 7, 2012.
Giant Improper Ferroelectricity in the Ferroaxial Magnet CaMnO
R. D. Johnson, L. C. Chapon, D. D. Khalyavin, P. Manuel, P. G. Radaelli et al.
In rhombohedral CaMnO, an improper ferroelectric polarization of magnitude 2870 [mu]C m is induced by an incommensurate helical magnetic structure that evolves below T=90 K. The electric polarization was found to be constrained to the high symmetry threefold rotation axis of the crystal structure ... [Phys. Rev. Lett. 108, 067201 ] published .
Triviality problem and high-temperature expansions of higher susceptibilities for the Ising and scalar-field models in four-, five-, and six-dimensional lattices
P. Butera and M. Pernici
High-temperature expansions are presently the only viable approach to the numerical calculation of the higher susceptibilities for the spin and the scalar-field models on high-dimensional lattices. The critical amplitudes of these quantities enter into a sequence of universal amplitude ratios that d ... [Phys. Rev. E 85, 021105 ] published .
Coexisting pseudogap, charge-transfer-gap, and Mott-gap energy scales in the resonant inelastic x-ray scattering spectra of electron-doped cuprate superconductors
Susmita Basak, Tanmoy Das, Hsin Lin, M. Z. Hasan, R. S. Markiewicz et al.
We present a computation of Cu K-edge resonant inelastic x-ray scattering (RIXS) spectra for electron-doped cuprates, which includes coupling to bosonic fluctuations. Comparison with experiment over a wide range of energy and momentum transfers allows us to identify the signatures of three key norma ... [Phys. Rev. B 85, 075104 ] published .
Publisher's Note: BT phase diagram of CoCrO in magnetic fields up to 14 T [Phys. Rev. B 85, 012101 (2012)]
A. V. Pronin, M. Uhlarz, R. Beyer, T. Fischer, J. Wosnitza et al.
Abstract not available. [Phys. Rev. B 85, 069901 ] published .
Structure of the oxygen-annealed chalcogenide superconductor FeTeSeO
Hefei Hu, Jian-Min Zuo, Mao Zheng, James N. Eckstein, Wan Kyu Park et al.
The as-grown single crystal FeTeSe with the tetragonal PbO-type structure is nonsuperconducting owing to the excess Fe. Superconductivity is induced after oxygen annealing with an onset and zero resistance transition temperature around 14.5 K and 11.5 K, respectively. The oxygen doping is evidenced ... [Phys. Rev. B 85, 064504 ] published .
Magneto-resistance of organic spin valves due to spin-polarized tunnel injection and extraction of charge carriers
A. Goswami, M. Yunus, P. P. Ruden, and D. L. Smith
Spin-polarized tunnel injection and extraction of charge carriers can give rise to magneto-resistance in organic spin valves. To describe this magneto-resistance, the tunneling process is modeled as a transfer of electrons through a thin insulating layer between a ferromagnetic contact and an organi ... [J. Appl. Phys. 111, 034505 (2012)] published Mon Feb 6, 2012.
Physical, electrical and magnetic properties of nano-sized Co-Cr substituted magnesium ferrites
Muhammad Javed Iqbal, Zahoor Ahmad, Turgut Meydan, and Yevgen Melikhov
Co-Cr substituted magnesium ferrite nanomaterials (MgCoCrFeO with x = 0.00.5) have been prepared by the polyethylene glycol assisted micro emulsion method. X-ray diffraction analysis confirms the single-phase cubic close-packed lattice formation of synthesized materials. Hysteresis loops are measure ... [J. Appl. Phys. 111, 033906 (2012)] published Mon Feb 6, 2012.
Mechanical properties of highly oriented FeSeTe superconductor
Jorge Luiz Pimentel Junior, Paulo Pureur, Cristiano Santos Lopes, Francisco Carlos Serbena, Carlos Eugenio Foerster et al.
We have synthesized highly oriented samples of the superconducting compound FeSeTe and investigated its mechanical properties. These samples were characterized by scanning electron microscopy (SEM) with energy-dispersive analysis, x-ray diffraction, and electrical resistivity. The measured critical ... [J. Appl. Phys. 111, 033908 (2012)] published Mon Feb 6, 2012.
Superconductivity in the vicinity of ferromagnetism in oxygen free perovskite MgCNi: An experimental and density functional theory study
Anuj Kumar, Rajveer Jha, Shiva Kumar Singh, Jagdish Kumar, P. K. Ahluwalia et al.
We report synthesis, structural, magnetic, specific heat, and density functional theory (DFT) studies on the MgCNi superconductor. Polycrystalline MgCNi samples are synthesized through the standard solid state reaction route and found to crystallize in the cubic perovskite structure with space group ... [J. Appl. Phys. 111, 033907 (2012)] published Mon Feb 6, 2012.
Phase instability of magnetic ground state in antiperovskite MnZnN: Giant magnetovolume effects related to magnetic structure
T. Hamada and K. Takenaka
We verified the intimate relation between magnetism and volume in MnZnN. The sample sintered at 900 degrees C is characterized by the Gamma triangular antiferromagnetic (AF) state with larger volume below 170 K. However, for the sample sintered at 700 degrees C, the re-entrant phase transition app ... [J. Appl. Phys. 111, 07A904 (2012)] published Mon Feb 6, 2012.
Magnetic properties and microstructures of iron oxide@mesoporous silica core-shell composite for applications in magnetic dye separation
Weichang Hao, Yang Xi, Jingwei Hu, Tianmin Wang, Y. Du et al.
In this report, hollow mesoporous silica (HMS) and iron oxide-hollow mesoporous silica (FeO@HMS) core-shell composite were prepared by a one-step facile fabrication method. Transmission electron microscopy, X-ray diffraction, N adsorptiondesorption isotherms, and vibrating sample magnetometer were u ... [J. Appl. Phys. 111, 07B301 (2012)] published Mon Feb 6, 2012.
Direct calorimetric measurements of isothermal entropy change on single crystal W-type hexaferrites at the spin reorientation transition
M. LoBue, V. Loyau, F. Mazaleyrat, A. Pasko, V. Basso et al.
We report on the magnetic field induced isothermal entropy change, Deltas(H, T), of W-type ferrite with CoZn substitution. Entropy measurements are performed by direct calorimetry. Single crystals of the composition BaCoZnFeO, prepared by the flux method, are measured at different fixed temperatures ... [J. Appl. Phys. 111, 07A905 (2012)] published Mon Feb 6, 2012.
Ab initio calculation of the local magnetic moment in titanium doped zinc oxide with a corrected-band-gap scheme
Bin Shao, Hong Liu, Jian Wu, and Xu Zuo
The local magnetic moment of Ti:ZnO is calculated from first principles by using the corrected-band-gap scheme (CBGS). The result shows that the system is magnetic with the magnetization of 0.699 [mu] per dopant. The origin of the local magnetic moment is considered to be the impurity band partially ... [J. Appl. Phys. 111, 07C301 (2012)] published Mon Feb 6, 2012.
Giant magnetostriction in tetragonally distorted antiperovskite manganese nitrides
T. Shimizu, T. Shibayama, K. Asano, and K. Takenaka
The discovery of giant magnetostriction exceeding 2000 ppm in MnCuN has stimulated the research of manganese antiperovskites from the perspective of forced magnetostriction. We discovered that MnSbN exhibits a large magnetostriction of up to 450 ppm in the tetragonally distorted ferromagnetic phase ... [J. Appl. Phys. 111, 07A903 (2012)] published Mon Feb 6, 2012.
Nanometer size effects on magnetic order in LaCaMnO (x = 0.5 and 0.6) manganites, probed by ferromagnetic resonance
A. I. Shames, E. Rozenberg, E. Sominski, and A. Gedanken
The data on X-band ferromagnetic resonance (FMR) in the half and electron-doped LaCaMnO (Ca0.5) and LaCaMnO (Ca0.6) nano-crystals and bulk ceramics are reported. The FMR data for considered nano-samples appeared to be strongly different, reflecting a difference in their magnetic/electronic order. An ... [J. Appl. Phys. 111, 07D701 (2012)] published Mon Feb 6, 2012.
The partitioning of Dy and Tb in NdFeB magnets: A first-principles study
X. B. Liu and Z. Altounian
Doping with Dy/Tb is a current solution to improve the coercivity and the operating temperature of NdFeB magnets, by increasing the magnetocrystalline anisotropy of the (Nd, Dy/Tb)FeB (2:14:1) phase. The efficiency of Dy/Tb doping depends on the distribution of Dy/Tb in the multi-phase microstructur ... [J. Appl. Phys. 111, 07A701 (2012)] published Mon Feb 6, 2012.
Effect of P addition on nanocrystallization and high temperature magnetic properties of low B and Nb containing FeCo nanocomposites
Rajat K. Roy, S. Shen, S. J. Kernion, and M. E. McHenry
The P content dependencies of the nanocrystallization behaviors and high temperature magnetic properties of the FeCoSi(BP)NbCu (Y = 0, 0.2, and 0.3) alloys have been investigated. Alloys were prepared by melt spinning and subsequently annealed in an argon atmosphere to induce nanocrystallization. P ... [J. Appl. Phys. 111, 07A301 (2012)] published Mon Feb 6, 2012.
Magnetization states and switching in narrow-gapped ferromagnetic nanorings
Jie Li, Sheng Zhang, Chris Grigas, Rajiv Misra, Jason Bartell et al.
We study permalloy nanorings that are lithographically fabricated with narrow gaps that break the rotational symmetry of the ring while retaining the vortex ground state, using both micromagnetic simulations and magnetic force microscopy (MFM). The vortex chirality in these structures can be readily ... [AIP Advances 2, 012136 (2012)] published Mon Feb 6, 2012.
Terahertz magnetic field induced coherent spin precession in YFeO
Runze Zhou, Zuanming Jin, Gaofang Li, Guohong Ma, Zhenxiang Cheng et al.
We present the magnetic dipole transition at 0.299 THz excited by magnetic component of terahertz electromagnetic pulse in an antiferromagnetic YFeO crystal. The impulsive magnetic field of the terahertz pulse tilts the macroscopic magnetization, causing deviation from the equilibrium position, whic ... [Appl. Phys. Lett. 100, 061102 (2012)] published Mon Feb 6, 2012.
Twin-Foucault imaging method
Ken Harada (原田研)
A method of Lorentz electron microscopy, which enables observation two Foucault images simultaneously by using an electron biprism instead of an objective aperture, was developed. The electron biprism is installed between two electron beams deflected by 180 degrees magnetic domains. Potential appli ... [Appl. Phys. Lett. 100, 061901 (2012)] published Mon Feb 6, 2012.
Entropy change linked to the magnetic field induced Morin transition in Hematite nanoparticles
J. M. Pastor, J. I. Perez-Landazabal, C. Gomez-Polo, V. Recarte, S. Larumbe et al.
The most stable form of iron oxide is Hematite (alpha-FeO), which has interesting electronic, catalytic, and magnetic properties showing size dependent characteristics. At room temperature, Hematite is weakly ferromagnetic with a rhombohedral corundum structure. Upon cooling, the structure undergoes ... [Appl. Phys. Lett. 100, 063102 (2012)] published Mon Feb 6, 2012.
Methyl group rotation, H spin-lattice relaxation in an organic solid, and the analysis of nonexponential relaxation
Peter A. Beckmann and Evan Schneider
We report H spin-lattice relaxation measurements in polycrystalline 4,4-dimethoxybiphenyl at temperatures between 80 and 300 K at NMR frequencies of omega/2pi = 8.50, 22.5, and 53.0 MHz. The data are interpreted in terms of the simplest possible Bloch-Wangsness-Redfield methyl group hopping model. D ... [J. Chem. Phys. 136, 054508 (2012)] published Mon Feb 6, 2012.
Electrically detected spin echoes of donor nuclei in silicon
D. R. McCamey, C. Boehme, G. W. Morley, and J. van Tol
The ability to electrically probe the spin properties of solid state systems underlies a wide variety of emerging technologies. Here, we demonstrate the electrical readout of the nuclear spin states of phosphorus donors in silicon in the coherent regime with modified Hahn echo sequences. We find tha ... [Phys. Rev. B 85, 073201 ] published .
Regimes of flux transport at microwave frequencies in nanostructured high-T films
R. Wordenweber, E. Hollmann, J. Schubert, R. Kutzner, and G. Panaitov
We report on combined dc and microwave electronic measurements of magnetic flux transport in micron and submicron-patterned high-T films. In a given temperature regime below the superconducting transition temperature T, the current-driven flux transport is restricted to flux motion guided by the sub ... [Phys. Rev. B 85, 064503 ] published .
Asymmetric magnetization reversal in dipolarly coupled spin valve structures with perpendicular magnetic anisotropy
M. Gottwald, M. Hehn, D. Lacour, T. Hauet, F. Montaigne et al.
Magnetization reversal has been studied in a CoTb/Cu/CoTb system, which is a perpendicularly magnetized ferrimagnetic bilayer separated by a nonmagnetic layer. The CoTb (soft) layer (SL) exhibits a switching field much lower than the CoTb (hard) layer (HL), which enabled us to study the magnetizatio ... [Phys. Rev. B 85, 064403 ] published .
Complex mixed state of the Pauli-limited superconductor CeCoIn
X. Gratens, L. Mendonca-Ferreira, Y. Kopelevich, N. F. Oliveira, Jr., R. R. Urbano et al.
Magnetization measurements were performed on CeCoIn at temperatures down to 20 mK and magnetic fields up to 17 T applied along different crystallographic orientations. For field configurations nearly parallel to the ab plane (theta<~40 and T<=50 mK), we have found an intriguing vortex dynamics regi ... [Phys. Rev. B 85, 054502 ] published .
Ordering process and ferroelectricity in a spinel derived from FeVO
Q. Zhang, K. Singh, F. Guillou, C. Simon, Y. Breard et al.
The spinel FeVO is known to exhibit peculiar physical properties, which is generally ascribed to the unusual presence of two cations showing a pronounced interplay between spin, orbital, and lattice degrees of freedom (Fe and V on the tetrahedral and octahedral sites, respectively). The present work ... [Phys. Rev. B 85, 054405 ] published .