Manganese-hydrogen complexes in GaMnN
C. Bihler, U. Gerstmann, M. Hoeb, T. Graf, M. Gjukic et al.
The effects of hydrogenation on Mn-doped GaN are studied with electron-paramagnetic resonance (EPR), local vibrational mode (LVM) spectroscopy, and density-functional theory (DFT) calculations. With EPR, we find two distinct Mn complexes which, in particular, differ in the size and orientation of th ... [Phys. Rev. B 80, 205205 (2009)] published Fri Nov 20, 2009.
Two distinct ferroelectric phases in the multiferroic Y-type hexaferrite BaMgFeO
Hajime Sagayama, Kouji Taniguchi, Nobuyuki Abe, Taka-hisa Arima, Yusaku Nishikawa et al.
The magnetic phase diagram of the Y-type hexaferrite BaMgFeO has been studied using single-crystal neutron diffraction. The result indicates successive phase transitions where the magnetic modulation wave number changed discontinuously when a magnetic field is applied and the temperature is varied. ... [Phys. Rev. B 80, 180419 (2009)] published Fri Nov 20, 2009.
Quantum phase transition of the one-dimensional transverse-field compass model
Ke-Wei Sun and Qing-Hu Chen
The quantum phase transition (QPT) of the one-dimensional (1D) quantum compass model in a transverse magnetic field is studied in this paper. An exact solution is obtained by using an extended Jordan and Wigner transformation to the pseudospin operators. The fidelity susceptibility, the concurrence, ... [Phys. Rev. B 80, 174417 (2009)] published Fri Nov 20, 2009.
Mechanism of exchange bias for isolated nanoparticles embedded in an antiferromagnetic matrix
Valera P. Shcherbakov, Karl Fabian, and Suzanne A. McEnroe
Single magnetic nanodots, exchange coupled to an antiferromagnetic (AF) matrix, can produce large exchange bias, while superparamagnetic behavior of the nanodots is suppressed. The exchange bias originates from the formation of a (quasi)spherical domain wall inside the AF matrix when the particle mo ... [Phys. Rev. B 80, 174419 (2009)] published Fri Nov 20, 2009.
Two magnetic Gruneisen parameters in the ferromagnetic superconductor UGe
F. Hardy, C. Meingast, V. Taufour, J. Flouquet, H. v. Lohneysen et al.
We report ambient-pressure magnetization, heat capacity, and thermal-expansion measurements of the ferromagnetic superconductor UGe in high magnetic fields. An analysis of the magnetic heat capacity derived from both magnetization and specific-heat data shows that UGe is well described in the framew ... [Phys. Rev. B 80, 174521 (2009)] published Fri Nov 20, 2009.
Transition from spin-density-wave to layered antiferromagnetic state induced by hydrogen as a test for the origin of spin-density waves in chromium
V. M. Uzdin, H. Zabel, A. Remhof, and B. Hjorvarsson
Neutron scattering experiments of Cr/V(001) superlattices are discussed, which show that the incommensurate spin-density-wave (SDW) in thick Cr layers becomes suppressed when the V spacer layers are loaded with hydrogen. The hydrogen loading triggers a transition from the incommensurate SDW state to ... [Phys. Rev. B 80, 174418 (2009)] published Fri Nov 20, 2009.
Model of Quasiparticles Coupled to a Frequency-Dependent Charge-Density-Wave Order Parameter in Cuprate Superconductors
G. Seibold, M. Grilli, and J. Lorenzana
We investigate a model where superconducting electrons are coupled to a frequency dependent charge-density wave order parameter Delta(omega). Our approach can reconcile the simultaneous existence of low-energy Bogoljubov quasiparticles and high energy electronic order as observed in scanning tunneli ... [Phys. Rev. Lett. 103, 217005 (2009)] published Fri Nov 20, 2009.
Flux pinning properties in BaMO (M=Zr,Sn) nanorod-introduced ErBaCuO films
Satoshi Awaji, Masafumi Namba, Kazuo Watnabe, Shun Ito, Eiji Aoyagi et al.
Flux pinning properties on the ErBaCaO films with the nanoscaled and columnar-shaped BaMO (BMO,M=Zr,Sn) precipitates, i.e., nanorods, were investigated systematically based on the microstructure, critical current density J and irreversibility field B properties in high magnetic fields. We found that ... [J. Appl. Phys. 106, 103915 (2009)] published Fri Nov 20, 2009.
Electrical control of magnetic remanent states in a magnetoelectric layered nanostructure
Tien-Kan Chung, Kin Wong, Scott Keller, Kang L. Wang, and Gregory P. Carman
We report experimental results on electrical control of magnetic remanent states (i.e., nanoscale remanent domain patterns) in a magnetoelectric layered nanostructure, Ni nanobar/lead zirconate titanate film. First, with application of different external magnetic fields as a baseline characterizatio ... [J. Appl. Phys. 106, 103914 (2009)] published Fri Nov 20, 2009.
Nonperturbative theory of type-II superconductivity in the presence of a strong Pauli paramagnetic effect
V. Zhuravlev and T. Maniv
The unusual low-temperature superconducting (SC) phase transitions following the competition between orbital and spin electron pair breaking, characterizing clean, heavy fermion, strongly type-II superconductors at high magnetic fields, are investigated within a nonperturbaive approach, which enable ... [Phys. Rev. B 80, 174520 (2009)] published Thu Nov 19, 2009.
Toroidal moment in the molecular magnet V
A. K. Zvezdin, V. V. Kostyuchenko, A. I. Popov, A. F. Popkov, and A. Ceulemans
Quantum-mechanical calculations predict the existence of toroidal spin structure in the molecular magnet V. It is shown that nonzero toroidal moment arises from symmetry violation of the exchange interactions between spins of the base triangle of the V molecule due to the Jahn-Teller effect. It is e ... [Phys. Rev. B 80, 172404 (2009)] published Thu Nov 19, 2009.
High-temperature ferromagnetism by means of oriented nanocolumns: Co clustering in (Zn,Co)O
N. Jedrecy, H. J. von Bardeleben, and D. Demaille
In order to provide insight into the magnetic properties of semiconductors with ferromagnetic inclusions, we present a thorough quantitative analysis of (Zn,Co)O films with high Co concentration, which give rise to high saturation magnetization values (~110 kA m) at room temperature. From the orien ... [Phys. Rev. B 80, 205204 (2009)] published Thu Nov 19, 2009.
Electron spin decoherence in diluted magnetic quantum wells
P. M. Shmakov, A. P. Dmitriev, and V. Yu. Kachorovskii
We study electron-spin dynamics in diluted magnetic quantum wells. The electrons are coupled by exchange interaction with randomly distributed magnetic ions polarized by magnetic field B. This coupling leads to both spin relaxation and spin decoherence. We demonstrate that even very small spatial fl ... [Phys. Rev. B 80, 193205 (2009)] published Thu Nov 19, 2009.
Scaling of the superfluid density in strongly underdoped YBaCuO: Evidence for a Josephson phase
C. C. Homes
Recent measurements on extremely underdoped YBaCuO [Phys. Rev. Lett. 99, 237003 (2007)] have allowed the critical temperature T, superfluid density rho[equivalent]rho(T<
Effect of microstructure on magnetic properties and anisotropy distributions in Co/Pd thin films and nanostructures
Justin M. Shaw, Hans T. Nembach, T. J. Silva, Stephen E. Russek, Roy Geiss et al.
The structure of Co/Pd multilayers has a strong effect on the localized anisotropy distribution within a film and on the resulting switching properties of nanostructures fabricated from identical material. By varying the underlying seed layer in sputtered films, the microstructure can be controlled ... [Phys. Rev. B 80, 184419 (2009)] published Thu Nov 19, 2009.
Finite-temperature spin dynamics and phase transitions in spin-orbital models
C.-C. Chen, B. Moritz, J. van den Brink, T. P. Devereaux, and R. R. P. Singh
We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition, consistent with that of a two-dimensional Ising model, to an orbi ... [Phys. Rev. B 80, 180418 (2009)] published Thu Nov 19, 2009.
Spin-density wave in Cr: Nesting versus low-lying thermal excitations
Veerle Vanhoof, Michel Rots, and Stefaan Cottenier
It is well known that present versions of density functional theory do not predict the experimentally observed spin-density wave state to be the ground state of Cr. Recently, a so-called nodon model has been proposed as an alternative way to reconcile theory and experiment: the ground state of Cr is ... [Phys. Rev. B 80, 184420 (2009)] published Thu Nov 19, 2009.
Competing interactions in ferromagnetic/antiferromagnetic perovskite superlattices
Y. Takamura, F. Yang, N. Kemik, E. Arenholz, M. D. Biegalski et al.
Soft x-ray magnetic dichroism, magnetization, and magnetotransport measurements demonstrate that the competition between different magnetic interactions (exchange coupling, electronic reconstruction, and long-range interactions) in LaSrFeO(LSFO)/LaSrMnO(LSMO) perovskite oxide superlattices leads to ... [Phys. Rev. B 80, 180417 (2009)] published Thu Nov 19, 2009.
Adjustable resonance frequency and linewidth by Zr doping in Co thin films
Changjun Jiang, Desheng Xue, Dangwei Guo, and Xiaolong Fan
CoZr (40 nm) thin films with different Zr compositions were grown on silicon substrates by radio frequency magnetron sputtering. The coercivity decreased with an increase in the Zr composition. A uniaxial anisotropy existed in the CoZr films, and the anisotropy field of the films decreased from 55 t ... [J. Appl. Phys. 106, 103910 (2009)] published Thu Nov 19, 2009.
Field dependence of the adiabatic temperature change in second order phase transition materials: Application to Gd
V. Franco, A. Conde, J. M. Romero-Enrique, Y. I. Spichkin, V. I. Zverev et al.
The field dependence of the adiabatic temperature change DeltaT of second order phase transition materials is studied, both theoretically and experimentally. Using scaling laws, it is demonstrated that, at the Curie temperature, the field dependence of DeltaT is characterized by H. Therefore, as the ... [J. Appl. Phys. 106, 103911 (2009)] published Thu Nov 19, 2009.
Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: Second-order quadrupolar and resonance offset effects
Sharon E. Ashbrook and Stephen Wimperis
Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of small resonance offset and second-order quadrupolar interactions has been investigated using both exact and approximate theoretical and experimental nuclear magnetic resonance (NMR) approaches. In the presence of second-order quadrupolar ... [J. Chem. Phys. 131, 194509 (2009)] published Thu Nov 19, 2009.
Superparamagnetic limit to spin-polarized vacuum tunneling from Fe-coated W(001) tips
Y. R. Niu and M. S. Altman
Superparamagnetic fluctuations of magnetization in thin Fe films that coat a sharp W(001) tip are evident in the spin polarization of field emitted electrons. Fluctuations of polarization between four transverse directions that align with the tip directions are consistent with the in-plane biaxial ... [Appl. Phys. Lett. 95, 203113 (2009)] published Thu Nov 19, 2009.
Local Current Injection into Mesoscopic Superconductors for the Manipulation of Quantum States
M. V. Milosevic, A. Kanda, S. Hatsumi, F. M. Peeters, and Y. Ootuka
We perform strategic current injection in a small mesoscopic superconductor and control the (non)equilibrium quantum states in an applied homogeneous magnetic field. In doing so, we realize a current-driven splitting of multiquanta vortices, current-induced transitions between states with different ... [Phys. Rev. Lett. 103, 217003 (2009)] published Thu Nov 19, 2009.
Photon absorption edge in superconductors and gapped one-dimensional systems
V. V. Mkhitaryan, E. G. Mishchenko, M. E. Raikh, and L. I. Glazman
Opening of a gap in the low-energy excitations spectrum affects the power-law singularity in the photon absorption spectrum A(Omega). In the normal state, the singularity, A(Omega)[proportional][D/(OmegaOmega)], is characterized by an interaction-dependent exponent alpha. On the contrary, in the sup ... [Phys. Rev. B 80, 205416 (2009)] published Wed Nov 18, 2009.
Elastic constants of the single crystalline Yb based heavy-fermion compound YbCoZn
Yoshiki Nakanishi, Takuya Fujino, Kankichi Ito, Mitsuteru Nakamura, Masahito Yoshizawa et al.
Ultrasonic measurements have been carried out on the heavy-fermion compound YbCoZn to investigate the elastic properties and the 4f electric state of Yb ion. A strong temperature dependence at low temperature was found in elastic constants C, (CC)/2, and C of YbCoZn. Furthermore, the elastic constan ... [Phys. Rev. B 80, 184418 (2009)] published Wed Nov 18, 2009.
Anisotropy of the spin density wave onset for (TMTSF)PF in a magnetic field
Ya. A. Gerasimenko, V. A. Prudkoglyad, A. V. Kornilov, V. M. Pudalov, V. N. Zverev et al.
In order to study the spin density wave transition temperature (T) in (TMTSF)PF as a function of magnetic field, we measured the magnetoresistance R in fields up to 19 T. Measurements were performed for three field orientations B||a,b and c at ambient pressure and at P=5 kbar, that is nearly the cr ... [Phys. Rev. B 80, 184417 (2009)] published Wed Nov 18, 2009.
Collective cavity mode excitations in arrays of Josephson junctions
I. Ottaviani, M. Cirillo, M. Lucci, V. Merlo, M. Salvato et al.
We report on oscillations of a Josephson-junction system revealing a close analogy with fundamental effects known in laser physics. The experiments are performed on series arrays of junctions whose IV curves show evidence of a mode in which all the junctions oscillate in synchronism on resonances ap ... [Phys. Rev. B 80, 174518 (2009)] published Wed Nov 18, 2009.
Intrinsic pinning on structural domains in underdoped single crystals of Ba(FeCo)As
R. Prozorov, M. A. Tanatar, N. Ni, A. Kreyssig, S. Nandi et al.
Critical current density was studied in single crystals of Ba(FeCo)As for the values of x spanning the entire doping phase diagram. A noticeable enhancement was found for slightly underdoped crystals with the peak at x=0.058. Using a combination of polarized-light imaging, x-ray diffraction and magn ... [Phys. Rev. B 80, 174517 (2009)] published Wed Nov 18, 2009.
Anisotropy barrier reduction in fast-relaxing Mn single-molecule magnets
Stephen Hill, Muralee Murugesu, and George Christou
An angle-swept high-frequency electron paramagnetic resonance (HFEPR) technique is described that facilitates efficient in situ alignment of single-crystal samples containing low-symmetry magnetic species such as single-molecule magnets (SMMs). This cavity-based technique involves recording HFEPR sp ... [Phys. Rev. B 80, 174416 (2009)] published Wed Nov 18, 2009.
Josephson effects in weakly coupled MgB intergrain nanobridges prepared by focused ion beam
Soon-Gul Lee, Sung-Hak Hong, Won Kyung Seong, and Won Nam Kang
We have fabricated weakly coupled intergrain nanobridges from MgB films by a focused ion beam (FIB) patterning technique and studied their transition properties. The bridges were nominally 300 nm wide and 100 nm long, and crossed a single grain boundary perpendicularly. The temperature-dependent res ... [Appl. Phys. Lett. 95, 202504 (2009)] published Wed Nov 18, 2009.
Theory of electromagnon resonances in the optical response of spiral magnets
A. Cano
The optical response of spiral magnets is studied theoretically, with special attention to its electromagnon features. We show that these features trace back to the resonant magnetoelectric response resulting from the spiral ordering (irrespective of any concomitant ferroelectricity). This response, ... [Phys. Rev. B 80, 180416 (2009)] published Tue Nov 17, 2009.
Theory of small charge solitons in one-dimensional arrays of Josephson junctions
Stephan Rachel and Alexander Shnirman
We identify and investigate the parameter regime of small charge solitons in one-dimensional arrays of Josephson junctions. We obtain the dispersion relation of the soliton and show that it unexpectedly flattens in the outer region of the Brillouin zone. We demonstrate Lorentz contraction of the sol ... [Phys. Rev. B 80, 180508 (2009)] published Tue Nov 17, 2009.
Ferromagnetic resonance linewidth in ultrathin films with perpendicular magnetic anisotropy
J.-M. Beaujour, D. Ravelosona, I. Tudosa, E. E. Fullerton, and A. D. Kent
Transition-metal ferromagnetic films with perpendicular magnetic anisotropy (PMA) have ferromagnetic resonance (FMR) linewidths that are one order of magnitude larger than soft magnetic materials, such as pure iron (Fe) and Permalloy (NiFe) thin films. A broadband FMR setup has been used to investig ... [Phys. Rev. B 80, 180415 (2009)] published Tue Nov 17, 2009.
Local density of states and superconducting gap in the iron chalcogenide superconductor FeSeTe observed by scanning tunneling spectroscopy
Takuya Kato, Yoshikazu Mizuguchi, Hiroshi Nakamura, Tadashi Machida, Hideaki Sakata et al.
We report on the investigation of the quasiparticle local density of states and superconducting gap in the iron chalcogenide superconductor FeSeTe(T~14 K). The surface of a cleaved crystal revealed an atomic square lattice, superimposed on the inhomogeneous background, with a lattice constant of ~3 ... [Phys. Rev. B 80, 180507 (2009)] published Tue Nov 17, 2009.
Temperature-dependent critical currents in superconducting YBaCuO and ferromagnetic LaCaMnO hybrid structures
M. Djupmyr, S. Soltan, H.-U. Habermeier, and J. Albrecht
The local critical current density in thin-film hybrid structures of high-temperature superconducting YBaCuO and ferromagnetic LaCaMnO (LCMO) is measured with high accuracy using a quantitative magneto-optical method. The superconducting films are grown onto vicinal cut substrates where step-flow gr ... [Phys. Rev. B 80, 184507 (2009)] published Tue Nov 17, 2009.
Magnetostructural transition in GdSbGe
A. S. Chernyshov, Ya. Mudryk, D. Paudyal, V. K. Pecharsky, K. A. Gschneidner, Jr. et al.
Magnetic and crystallographic properties of GdSbGe were investigated using dc magnetization, ac magnetic susceptibility, and heat capacity of an oriented single crystal, combined with temperature and magnetic field dependent x-ray powder diffraction. The compound undergoes an unusual magnetostructur ... [Phys. Rev. B 80, 184416 (2009)] published Tue Nov 17, 2009.
Determining the size distribution of magnetic nanoparticles based on analysis of magnetization curves
Su-Peng Yu, Yi-Hsien Liu, An-Cheng Sun, and Jen-Hwa Hsu
This study develops a direct scheme that is based on the magnetization curve of magnetic nanoparticles in the medium-field region above the blocking temperature to extract information on the size of particles and the uniformity thereof. The magnetization curve was fitted with a computer software tha ... [J. Appl. Phys. 106, 103905 (2009)] published Tue Nov 17, 2009.
Asymmetric magnetization reversal process in Co nanohill arrays
W. O. Rosa, L. Martinez, M. Jaafar, A. aAsenjo, and M. Vazquez
Co thin films deposited by sputtering onto nanostructured polymer [poly(methyl methacrylate)] were prepared following replica-antireplica process based on porous alumina membrane. In addition, different capping layers were deposited onto Co nanohills. Morphological and compositional analysis was per ... [J. Appl. Phys. 106, 103906 (2009)] published Tue Nov 17, 2009.
The effect of MgO barrier on the structure and magnetic properties of CoMnSi films on n-Si(100) substrates
M. A. I. Nahid, M. Oogane, H. Naganuma, and Y. Ando
We investigated the structure and magnetic properties of CoMnSi/MgO/n-Si(100) films with the goal of achieving efficient spin injection. The CoMnSi films were fabricated by dc sputtering and post annealed at 400 degrees C for 1 h. They were oriented along the direction with a MgO barrier layer. A ... [J. Appl. Phys. 106, 103907 (2009)] published Tue Nov 17, 2009.
Coexistence of magnetic and ferroelectric behaviors of pyrochlore HoTiO
X. W. Dong, K. F. Wang, S. J. Luo, J. G. Wan, and J.M. Liu
Rare-earth titanate cubic pyrochlore HoTiO ceramics are prepared by the standard solid state reaction. The magnetic, dielectric, and ferroelectric behaviors are measured in order to investigate the multiferroic behaviors of HoTiO. Upon the gradual spin ordering sequence with decreasing temperature, ... [J. Appl. Phys. 106, 104101 (2009)] published Tue Nov 17, 2009.
Magnetic transitions in alpha-FeO nanowires
C. Diaz-Guerra, L. Perez, J. Piqueras, and M. F. Chioncel
Magnetic transitions in single-crystal alpha-FeO (hematite) nanowires, grown by thermal oxidation of iron powder, have been studied in the range of 51023 K with a superconducting quantum interference device below room temperature and with a vibrating sample magnetometer at higher temperatures. The ... [J. Appl. Phys. 106, 104302 (2009)] published Tue Nov 17, 2009.
Evidence for Two Competing Order Parameters in Underdoped Cuprate Superconductors from a Model Analysis of Fermi-Arc Effects
Andres Greco
Preformed pairs above T and the two-gap scenarios are two main proposals for describing the low-doping pseudogap phase of high-T cuprates. Very recent angle-resolved photoemission experiments have shown features which were interpreted as evidence for preformed pairs. Here it is shown that those resu ... [Phys. Rev. Lett. 103, 217001 (2009)] published Tue Nov 17, 2009.
Effect of stacking order on the magnetic and transport properties of bilayer-based oxide superlattices with inversion symmetry
P. Padhan and W. Prellier
SrRuOSrMnO multilayers with heterointerfaces of similar inversion symmetry were fabricated. The SrTiO/[SrMnO/SrRuO] multilayer shows lower Curie temperature, smaller magnetization and larger magnetoresistance compared to SrTiO/[SrRuO/SrMnO] multilayer. The variations of these properties with the inv ... [Appl. Phys. Lett. 95, 203107 (2009)] published Mon Nov 16, 2009.
Element-specific magnetometry of EuS nanocrystals
Rachel S. Selinsky, David J. Keavney, Matthew J. Bierman, and Song Jin
A soft x-ray absorption and x-ray magnetic circular dichroism (XMCD) study of the ferromagnetism in solution-grown EuS nanocrystals (NCs) is reported. The absorption edges of Eu M and M, S K, O K, and P K were probed to determine elementally specific contributions to the magnetism of EuS NCs. Differ ... [Appl. Phys. Lett. 95, 202501 (2009)] published Mon Nov 16, 2009.
Enhanced nonvolatile resistive switching in dilutely cobalt doped TiO
Kashinath A. Bogle, Mukesh N. Bachhav, Meenal S. Deo, Nagarajan Valanoor, and Satishchandra B. Ogale
Incorporation of dilute concentration of dopant having a valence state different than that of the host cation enables controlled incorporation proximity vacancy defects for local charge balance. Since nonvolatile resistive switching is a phenomenon tied to such defects, it can be expected to be infl ... [Appl. Phys. Lett. 95, 203502 (2009)] published Mon Nov 16, 2009.
Differences in the high-energy kink between hole- and electron-doped high-T superconductors
M. Ikeda, T. Yoshida, A. Fujimori, M. Kubota, K. Ono et al.
We have performed an angle-resolved photoemission spectroscopy (ARPES) study of NdCeCuO (NCCO) in order to elucidate the origin of the high-energy kink (HEK) observed in the high-T superconductors (HTSCs). The energy scale of the HEK in NCCO is large compared with that in hole-doped HTSCs, consisten ... [Phys. Rev. B 80, 184506 (2009)] published Mon Nov 16, 2009.
Transverse instabilities of multiple vortex chains in magnetically coupled NbSe/permalloy superconductor/ferromagnet bilayers
G. Karapetrov, M. V. Milosevic, M. Iavarone, J. Fedor, A. Belkin et al.
Using scanning tunneling microscopy and Ginzburg-Landau simulations, we explore vortex configurations in magnetically coupled NbSe/permalloy superconductor/ferromagnet bilayer. The permalloy film with stripe domain structure induces periodic local magnetic induction in the superconductor, creating a ... [Phys. Rev. B 80, 180506 (2009)] published Mon Nov 16, 2009.
Antiferromagnetic to valence-bond-solid transitions in two-dimensional SU(N) Heisenberg models with multispin interactions
Jie Lou, Anders W. Sandvik, and Naoki Kawashima
We study two-dimensional Heisenberg antiferromagnets with additional multispin interactions which can drive the system into a valence-bond-solid state. For standard SU(2) spins, we consider both four- and six-spin interactions. We find continuous quantum phase transitions with the same critical expo ... [Phys. Rev. B 80, 180414 (2009)] published Mon Nov 16, 2009.
Measurement of spin memory lengths in PdNi and PdFe ferromagnetic alloys
H. Z. Arham, Trupti S. Khaire, R. Loloee, W. P. Pratt, Jr., and Norman O. Birge
Weakly ferromagnetic alloys are being used by several groups in the study of superconducting/ferromagnetic hybrid systems. Because spin-flip and spin-orbit scattering in such alloys disrupt the penetration of pair correlations into the ferromagnetic material, it is desirable to have a direct measure ... [Phys. Rev. B 80, 174515 (2009)] published Mon Nov 16, 2009.
Observation of a coherent optical phonon in the iron pnictide superconductor Ba(FeCo)As (x=0.06 and 0.08)
B. Mansart, D. Boschetto, A. Savoia, F. Rullier-Albenque, A. Forget et al.
We report the observation of a coherent lattice oscillation in a pnictide superconductor. A coherent fully symmetric optical phonon was detected in Ba(FeCo)As (x=0.06 and x=0.08) using time-resolved pump-probe reflectivity with 40 fs time resolution. The analysis of the phonon parameters for various ... [Phys. Rev. B 80, 172504 (2009)] published Mon Nov 16, 2009.
Determination of perpendicular magnetic anisotropy in ultrathin ferromagnetic films by extraordinary Hall voltage measurement
Kyoung-Woong Moon, Jae-Chul Lee, Sug-Bong Choe, and Kyung-Ho Shin
A magnetometric technique for detecting the magnetic anisotropy field of ferromagnetic films is described. The technique is based on the extraordinary Hall voltage measurement with rotating the film under an external magnetic field. By analyzing the angle-dependent Hall voltage based on the StonerWo ... [Rev. Sci. Instrum. 80, 113904 (2009)] published Mon Nov 16, 2009.
First order reversal curve diagrams of perpendicular magnetic anisotropy films
Jinhua Yin, Hongwei Zhang, Fengxia Hu, Baogen Shen, and L. Q. Pan
The exchange coupling and magnetic properties distributions in Co/Pd multilayer perpendicular magnetic anisotropy films with different magnetic properties are investigated using the experimental first order reversal curve (FORC) diagram with assistance of LandauLifshitzGilbert simulation. The simula ... [J. Appl. Phys. 106, 103901 (2009)] published Mon Nov 16, 2009.
Nanocrystalline metastable 2/17 and 1/12 precursors: A promising class of hard magnetic materials
L. Bessais, C. Djega-Mariadassou, H. Lassri, and N. Mliki
We present a general structure model relative to the metastable P6/mmm precursors of the I4/mmm RFeTi (R=Pr,Sm) and R[overline 3]m Sm(Fe,M) (M=Ga,Si) equilibrium phases. This model is based on the description of the binary RM compounds (s=vacancy rate, M=metal). The Rietveld analysis leads to stoi ... [J. Appl. Phys. 106, 103904 (2009)] published Mon Nov 16, 2009.
Angular dependence of magnetic properties in Ni nanowire arrays
R. Lavin, J. C. Denardin, J. Escrig, D. Altbir, A. Cortes et al.
The angular dependence of the remanence and coercivity of Ni nanowire arrays produced inside the pores of anodic alumina membranes has been studied. By comparing our analytical calculations with our measurements, we conclude that the magnetization reversal in this array is driven by means of the nuc ... [J. Appl. Phys. 106, 103903 (2009)] published Mon Nov 16, 2009.
Magnetically Hindered Chain Formation in Transition-Metal Break Junctions
A. Thiess, Y. Mokrousov, S. Heinze, and S. Blugel
Based on first-principles calculations, we demonstrate that magnetism impedes the formation of long chains in break junctions. We find a distinct softening of the binding energy of atomic chains due to the creation of magnetic moments that crucially reduces the probability of successful chain format ... [Phys. Rev. Lett. 103, 217201 (2009)] published Mon Nov 16, 2009.
Magnetoresistance in an asymmetric GaMnAs resonant tunneling diode
Edward Likovich, Kasey Russell, Wei Yi, Venkatesh Narayanamurti, Keh-Chiang Ku et al.
In a GaMnAs/AlGaAs resonant tunneling diode (RTD) structure, we observe that both the magnitude and polarity of magnetoresistance are bias dependent when tunneling from a three-dimensional GaMnAs layer through a two-dimensional GaMnAs quantum well. This magnetoresistance behavior results from a shif ... [Phys. Rev. B 80, 201307 (2009)] published Fri Nov 13, 2009.
High sensitivity of O NMR to p-d hybridization in transition metal perovskites: First principles calculations of large anisotropic chemical shielding
Daniel L. Pechkis, Eric J. Walter, and Henry Krakauer
A first principles embedded cluster approach is used to calculate O chemical shielding tensors, sigma-hat, in prototypical transition metal oxide ABO perovskite crystals. Our principal findings are (1) a large anisotropy of sigma-hat between deshielded sigma~=sigma and shielded sigma components (z a ... [J. Chem. Phys. 131, 184511 (2009)] published Fri Nov 13, 2009.
Functional renormalization-group study of the doping dependence of pairing symmetry in the iron pnictide superconductors
Ronny Thomale, Christian Platt, Jiangping Hu, Carsten Honerkamp, and B. Andrei Bernevig
We use the functional renormalization group to analyze the phase diagram of a four-band model for the iron pnictides subject to band interactions with certain A momentum dependence. We determine the parameter regimes where an extended s-wave pairing instability with and without nodes emerges. For el ... [Phys. Rev. B 80, 180505 (2009)] published Fri Nov 13, 2009.
Incommensurate spin correlation driven by frustration in BiCuPO
O. Mentre, E. Janod, P. Rabu, M. Hennion, F. Leclercq-Hugeux et al.
The magnetic properties of BiCuPO have been analyzed by means of magnetic-susceptibility and inelastic neutron-scattering measurements on powder samples by evaluating the spin-exchange interactions on the basis of density-functional calculations and by simulating the inelastic neutron scattering in ... [Phys. Rev. B 80, 180413 (2009)] published Fri Nov 13, 2009.
Oscillating spin-density pattern in gold metallocene and phthalocyanine molecules
Diego Carrascal, Lucas Fernandez-Seivane, and Jaime Ferrer
We present a theoretical study of the magnetic properties of the spin-1/2 dicyclopentadienyl metallocene (MCp) and phthalocyanine molecules that contain the transition-metal atoms M=Co, Cu, and Au. We find that the spin-density pattern of gold molecules shows a fully delocalized and oscillating beha ... [Phys. Rev. B 80, 184415 (2009)] published Fri Nov 13, 2009.
Theory of two-dimensional macroscopic quantum tunneling in YBaCuO Josephson junctions coupled to an LC circuit
Shiro Kawabata, Thilo Bauch, and Takeo Kato
We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a YBaCuO (YBCO) Josephson junction coupled to an LC circuit theoretically. Due to the coupling between the junction and the LC circuit, the macroscopic phase dynamics can be described as the escape process o ... [Phys. Rev. B 80, 174513 (2009)] published Fri Nov 13, 2009.
In-plane spin reorientation transition in a two-dimensional ferromagnetic/antiferromagnetic system studied using Monte Carlo simulations
J. H. Seok, H. Y. Kwon, S. S. Hong, Y. Z. Wu, Z. Q. Qiu et al.
We investigated the in-plane spin reorientation transition (SRT) in a two-dimensional ferromagnetic/antiferromagnetic system by using Monte Carlo simulation based on the Heisenberg model. The temperature-driven SRT in the ferromagnetic layer is studied for the case of that the antiferromagnetic laye ... [Phys. Rev. B 80, 174407 (2009)] published Fri Nov 13, 2009.
Muon spin relaxation studies of the frustrated quasi-two-dimensional square-lattice spin system Cu(Cl,Br)La(Nb,Ta)O: Evolution from spin-gap to antiferromagnetic state
Y. J. Uemura, A. A. Aczel, Y. Ajiro, J. P. Carlo, T. Goko et al.
We report muon spin relaxation ([mu]SR) and magnetic-susceptibility measurements on Cu(Cl,Br)La(Nb,Ta)O, which demonstrate: (a) the absence of static magnetism in (CuCl)LaNbO down to 15 mK confirming a spin-gapped ground state; (b) phase separation between partial volumes with a spin-gap and static ... [Phys. Rev. B 80, 174408 (2009)] published Fri Nov 13, 2009.
Transferred hyperfine interactions for Yb ions in CsCaF and CsNaYF single crystals: Experimental and ab initio study
M. L. Falin, O. A. Anikeenok, V. A. Latypov, N. M. Khaidukov, F. Callens et al.
The results of an electron-nuclear double resonance study of the cubic paramagnetic Yb center in CsNaYF and CsCaF single crystals are presented. The values and signs of the transferred hyperfine interaction (THFI) parameters for several neighboring shells are determined. It is found that the relevan ... [Phys. Rev. B 80, 174110 (2009)] published Fri Nov 13, 2009.
Prediction of electrically induced magnetic reconstruction at the manganite/ferroelectric interface
J. D. Burton and E. Y. Tsymbal
The control of magnetization via the application of an electric field, known as magnetoelectric coupling, is among the most fascinating and active research areas today. In addition to fundamental scientific interest, magnetoelectric effects may lead to new device concepts for data storage and proces ... [Phys. Rev. B 80, 174406 (2009)] published Fri Nov 13, 2009.
Angular dependence of the upper critical field of SrRuO
S. Kittaka, T. Nakamura, Y. Aono, S. Yonezawa, K. Ishida et al.
One of the remaining issues concerning the spin-triplet superconductivity of SrRuO is the strong limit of the in-plane upper critical field H at low temperatures. In this study, we clarified the dependence of H on the angle theta between the magnetic field and the ab plane at various temperatures, b ... [Phys. Rev. B 80, 174514 (2009)] published Fri Nov 13, 2009.
Quantum phase transition in (CuCl)La(NbTa)O
A. Kitada, Y. Tsujimoto, H. Kageyama, Y. Ajiro, M. Nishi et al.
We demonstrate the synthesis and magnetic properties of a quasi-two-dimensional frustrated quantum spin system (CuCl)La(NbTa)O. We observed persistence of the spin-singlet state in (CuCl)LaNbO up to x~0.4, accompanied by a slight reduction in the spin gap with increasing x. In spite of unaltered cel ... [Phys. Rev. B 80, 174409 (2009)] published Fri Nov 13, 2009.
Magnetic anisotropy tuned by interfacial engineering
N. Lei, D. H. Wei, C. S. Tian, S. H. Xiao, D. Z. Hou et al.
With continuous variable composition, an artificial pseudomorphic template of 1 ML CuAu was achieved by epitaxial growth on Cu(001), in which the magnetic anisotropy and the spin reorientation transition of Ni films were investigated in situ. The result clearly indicates that the strain induced prot ... [Appl. Phys. Lett. 95, 192506 (2009)] published Fri Nov 13, 2009.