Condensed Matter - Strongly Correlated Electrons

Magnetocaloric effect and refrigerant capacity in SmSrMnO (x = 0.42, 0.44, 0.46) manganites

Nicholas S. Bingham, Paula J. Lampen, The-Long Phan, Manh-Huong Phan, Seong-Cho Yu et al.
SmSrMnO (SSMO) with x ~ 0.44 shows a multi-critical phase diagram which includes antiferromagnetic, charge ordering, and ferromagnetic transitions that give rise to large magnetoresistive and magnetocaloric effects. In this study, we systematically investigated the magnetic transitions, magnetocalor ... [J. Appl. Phys. 111, 07D705 (2012)] published Mon Feb 13, 2012.

Properties of NaZn-type LaFeSi (x=1.4, 1.5) compound with the first-order phase transition

Q. Y. Dong, H. W. Zhang, J. Shen, J. Chen, J. R. Sun et al.
The investigations of dc magnetization, magnetic relaxation, specific heat, and electrical resistance for LaFeSi (x = 1.4, 1.5) compounds have been carried out. Obvious thermal and magnetic hysteresis indicates that they experience a first-order phase transition. The phase transition temperature T i ... [J. Appl. Phys. 111, 07E107 (2012)] published Mon Feb 13, 2012.

NMR Probing of the Spin Polarization of the nu=5/2 Quantum Hall State

M. Stern, B. A. Piot, Y. Vardi, V. Umansky, P. Plochocka et al.
Resistively detected nuclear magnetic resonance is used to measure the Knight shift of the As nuclei and determine the electron spin polarization of the fractional quantum Hall states of the second Landau level. We show that the 5/2 state is fully polarized within experimental error, thus confirming ... [Phys. Rev. Lett. 108, 066810 ] published .

Non-Kondo Mechanism for Resistivity Minimum in Spin Ice Conduction Systems

Masafumi Udagawa, Hiroaki Ishizuka, and Yukitoshi Motome
We present a mechanism of resistivity minimum in conduction electron systems coupled with localized moments, which is distinguished from the Kondo effect. Instead of the spin-flip process in the Kondo effect, electrons are elastically scattered by local spin correlations which evolve in a particular ... [Phys. Rev. Lett. 108, 066406 ] published .

Single-Ion Kondo Scaling of the Coherent Fermi Liquid Regime in CeLaNiGe

Adam P. Pikul, Ulrike Stockert, Alexander Steppke, Tomasz Cichorek, Stefanie Hartmann et al.
Thermodynamic and transport properties of the La-diluted Kondo lattice CeNiGe were studied in a wide temperature range. The Ce-rich alloys CeLaNiGe were found to exhibit distinct features of the coherent heavy Fermi liquid. At intermediate compositions (0.7<=x<=0.9), non-Fermi liquid properties have ... [Phys. Rev. Lett. 108, 066405 ] published .

Isospin of topological defects in Dirac systems

Igor F. Herbut
We study the Dirac quasiparticles in d-dimensional lattice systems of electrons in the presence of domain walls (d=1), vortices (d=2), or hedgehogs (d=3) of superconducting and/or insulating, order parameters, which appear as mass terms in the Dirac equation. Such topological defects have been known ... [Phys. Rev. B 85, 085304 ] published .

Quantum criticality of the sub-Ohmic spin-boson model

Stefan Kirchner, Kevin Ingersent, and Qimiao Si
We revisit the critical behavior of the sub-Ohmic spin-boson model. Analysis of both the leading and subleading terms in the temperature dependence of the inverse static local spin susceptibility at the quantum critical point, calculated using a numerical renormalization-group method, provides evide ... [Phys. Rev. B 85, 075113 ] published .

Determination of spin pumping as a source of linewidth in sputtered CoFe/Pd multilayers by use of broadband ferromagnetic resonance spectroscopy

Justin M. Shaw, Hans T. Nembach, and T. J. Silva
We performed a systematic study of damping in CoFe/Pd multilayers by use of broadband (160 GHz) ferromagnetic resonance (FMR) spectroscopy in the perpendicular geometry. The data were fitted with the conventional Landau-Lifshitz equation in conjunction with an inhomogeneous contribution to linewidth ... [Phys. Rev. B 85, 054412 ] published .

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.

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.

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.

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 .

Hierarchical Nature of the Quantum Hall Effects

Parsa Bonderson
I demonstrate that the wave function for a nu=n+nu-tilde quantum Hall state with Landau levels 0,1,&#x2026;,n-1 filled and a filling fraction nu-tilde quantum Hall state with 0

Hall Viscosity and Electromagnetic Response

Carlos Hoyos and Dam Thanh Son
We show that, for Galilean invariant quantum Hall states, the Hall viscosity appears in the electromagnetic response at finite wave numbers q. In particular, the leading q dependence of the Hall conductivity at small q receives a contribution from the Hall viscosity. The coefficient of the q term in ... [Phys. Rev. Lett. 108, 066805 ] published .

Competing orders in the Dirac-like electronic structure and the nonlinear sigma model with a topological term

Pouyan Ghaemi and Shinsei Ryu
The Dirac-like electronic structure can host a large number of competing orders in the form of mass terms. In particular, two different order parameters can be said to be dual to each other, when a static defect in one of them traps a quantum number (or charge) of the other. We discuss that such com ... [Phys. Rev. B 85, 075111 ] 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.

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.

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.

Non-Abelian Braiding of Lattice Bosons

Eliot Kapit, Paul Ginsparg, and Erich Mueller
We report on a numerical experiment in which we use time-dependent potentials to braid non-Abelian quasiparticles. We consider lattice bosons in a uniform magnetic field within the fractional quantum Hall regime, where nu, the ratio of particles to flux quanta, is near 1/2, 1, or 3/2. We introduce t ... [Phys. Rev. Lett. 108, 066802 ] published .

Interplay between interaction and chiral anomaly in the holographic approach

Ki-Seok Kim and Takuya Tsukioka
Strongly coupled conformal field theory appears to describe universal scaling around quantum criticality, where critical exponents reflect the nature of emergent excitations. In particular, novel symmetries can emerge from strong interactions that are expected to be responsible for quantum number fr ... [Phys. Rev. D 85, 045011 ] published .

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.

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.

Full configuration interaction perspective on the homogeneous electron gas

James J. Shepherd, George Booth, Andreas Gruneis, and Ali Alavi
Highly accurate results for the homogeneous electron gas (HEG) have only been achieved to date within a diffusion Monte Carlo (DMC) framework. Here, we introduce a recently developed stochastic technique, full configuration interaction quantum Monte Carlo (FCIQMC), which samples the exact wave funct ... [Phys. Rev. B 85, 081103 ] published .

Ground-state degeneracy in the Levin-Wen model for topological phases

Yuting Hu, Spencer D. Stirling, and Yong-Shi Wu
We study the properties of topological phases by calculating the ground-state degeneracy (GSD) of the two-dimensional Levin-Wen (LW) model. Here it is explicitly shown that the GSD depends only on the spatial topology of the system. Then we show that the ground state on a sphere is always nondegener ... [Phys. Rev. B 85, 075107 ] published .

Extended dual description of Mott transition beyond two-dimensional space

Yin Zhong, Ke Liu, and Hong-Gang Luo
Motivated by the recent paper of Mross and Senthil [Phys. Rev. B 84, 165126 (2011)], which provides a dual description for a Mott transition from a Fermi liquid to a quantum-spin liquid in two space dimensions, we extend their approach to higher-dimensional cases, and we provide explicit formalism i ... [Phys. Rev. B 85, 075106 ] 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 .

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.

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.

Superconductivity Induced by Longitudinal Ferromagnetic Fluctuations in UCoGe

T. Hattori, Y. Ihara, Y. Nakai, K. Ishida, Y. Tada et al.
From detailed angle-resolved NMR and Meissner measurements on a ferromagnetic (FM) superconductor UCoGe (T~2.5 K and T~0.6 K), we show that superconductivity in UCoGe is tightly coupled with longitudinal FM spin fluctuations along the c axis. We found that magnetic fields along the c axis (H||c) s ... [Phys. Rev. Lett. 108, 066403 ] published .

Giant negative magnetoresistance in high-mobility two-dimensional electron systems

A. T. Hatke, M. A. Zudov, J. L. Reno, L. N. Pfeiffer, and K. W. West
We report on a giant negative magnetoresistance in very high mobility GaAs/AlGaAs heterostructures and quantum wells. The effect is the strongest at B~=1 kG, where the magnetoresistivity develops a minimum emerging at T<~2 K. Unlike the zero-field resistivity which saturates at T~=2 K, the resistivi ... [Phys. Rev. B 85, 081304 ] published .

Itinerant half-metal spin-density-wave state on the hexagonal lattice. (arXiv:1202.2127v1 [cond-mat.str-el])

ePrint arXiv http://arXiv.org/

Charge carrier localisation in disordered graphene nanoribbons. (arXiv:1202.2202v1 [cond-mat.str-el])

ePrint arXiv http://arXiv.org/

Strain dependence of bonding and hybridization across the metal-insulator transition of VO2. (arXiv:1202.2286v1 [cond-mat.str-el])

ePrint arXiv http://arXiv.org/

Polarization-sensitive absorption of THz radiation by interacting electrons in chirally stacked multilayer graphene. (arXiv:1202.2302v1 [cond-mat.mes-hall])

ePrint arXiv http://arXiv.org/

Electric field control of the magnetic chiralities in ferroaxial multiferroic RbFe(MoO4)2. (arXiv:1202.2317v1 [cond-mat.str-el])

ePrint arXiv http://arXiv.org/

A model of magnetic order in hexagonal HoMnO3. (arXiv:1202.2321v1 [cond-mat.str-el])

ePrint arXiv http://arXiv.org/

A dynamical study of phase fluctuations and their critical slowing down in amorphous superconducting films. (arXiv:1010.2996v4 [cond-mat.supr-con] UPDATED)

ePrint arXiv http://arXiv.org/

Broadband microwave and time-domain terahertz spectroscopy of CVD grown graphene. (arXiv:1106.2472v2 [cond-mat.mtrl-sci] UPDATED)

ePrint arXiv http://arXiv.org/

Dimensional Evolution of Spin Correlations in the Magnetic Pyrochlore Yb2Ti2O7. (arXiv:1107.2377v2 [cond-mat.str-el] UPDATED)

ePrint arXiv http://arXiv.org/

Maximum entropy deconvolution of resonant inelastic x-ray scattering spectra. (arXiv:1107.4081v3 [cond-mat.str-el] UPDATED)

ePrint arXiv http://arXiv.org/

Self-consistent density functional calculations of the crystal field levels in lanthanide and actinide dioxides. (arXiv:1111.4137v2 [cond-mat.str-el] UPDATED)

ePrint arXiv http://arXiv.org/

Local spectral properties of Luttinger liquids: scaling versus nonuniversal energy scales. (arXiv:1111.7174v2 [cond-mat.str-el] UPDATED)

ePrint arXiv http://arXiv.org/

Simulation of Anyons Using Symmetric Tensor Network Algorithms. (arXiv:1202.1522v2 [cond-mat.str-el] UPDATED)

ePrint arXiv http://arXiv.org/