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Magnetic, specific heat, and structural properties of the equiatomic Cantor alloy system are reported for temperatures between 5 kelvin and 300 kelvin, and up to fields of 70 kilo-oersted. Magnetization measurements performed on as-cast,…

High entropy alloys (HEAs) are promising magnetocaloric materials with tunable operating temperature conditions using compositional modifications. Here, we combine experiments and first principles based spin modelling to engineer…

We have investigated the magnetic properties of Fe, Co, and Ni at finite temperatures on the basis of the first-principles dynamical coherent potential approximation (CPA) in order to clarify the role of the exchange interaction energy…

强关联电子 · 物理学 2015-05-27 Y. Kakehashi , M. Atiqur R. Patoary

We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab-initio electronic structure theory which includes disordered local moments and strong $f$-electron…

We present a semi-analytic theory for the Curie temperature in diluted magnetic semi-conductors that treats disorder effects exactly in the effective Heisenberg Hamiltonian, and spin fluctuations within a local RPA. The exchange couplings…

无序系统与神经网络 · 物理学 2015-06-24 Georges Bouzerar , Timothy Ziman , Josef Kudrnovsky

We discuss the properties of semiconducting bulk ZnO when substituted with the magnetic transition metal ions Mn and Co, with substituent fraction ranging from $x$ = 0.02 to $x$ = 0.15. The magnetic properties were measured as a function of…

材料科学 · 物理学 2009-11-10 G. Lawes , A. S. Risbud , A. P. Ramirez , Ram Seshadri

Recently, thermally-assisted-occupation density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] has been demonstrated to be an efficient and accurate electronic structure method for studying the ground-state…

化学物理 · 物理学 2026-03-03 Shaozhi Li , Jeng-Da Chai

An extended atomistic spin model allowing for studies of the finite temperature magnetic properties of alloys is proposed. The model is obtained by extending the Heisenberg Hamiltonian via a parameterization from a first principles basis,…

计算物理 · 物理学 2017-06-07 Fan Pan , Jonathan Chico , Anna Delin , Anders Bergman , Lars Bergqvist

A set of Modified Embedded Atom Method (MEAM) potentials for the interactions between Al, Si, Mg, Cu, and Fe was developed from a combination of each element's MEAM potential in order to study metal alloying. Previously published MEAM…

The high entropy alloy containing refractory metals Mo-Nb-Ta-W has a body centered cubic structure, which is not surprising given the complete mutual solubility in BCC solid solutions of all pairs of the constituent elements. However, first…

材料科学 · 物理学 2014-02-10 Michael Widom , William Paul Huhn , Soumyadipta Maiti , Walter Steurer

Finite-temperature properties of weakly doped antiferromagnets as modeled by the two-dimensional t-J model and relevant to underdoped cuprates are investigated by numerical studies of small model systems at low doping. Two numerical methods…

强关联电子 · 物理学 2007-05-23 D. Veberic , P. Prelovsek , H. G. Evertz

Magnetoelasticity plays a crucial role in numerous magnetic phenomena, including magnetocalorics, magnon excitation via acoustic waves, and ultrafast demagnetization/Einstein-de Haas effect. Despite a long-standing discussion on…

The magnetic response of nanostructures plays an important role on biomedical applications being strongly influenced by the magnetic anisotropy. In this work we investigate the role of temperature, particle concentration and nanoparticle…

应用物理 · 物理学 2019-02-20 V. R. R. Aquino , L. C. Figueiredo , J. A. H. Coaquira , M. H. Sousa , A. F. Bakuzis

Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in $S=1/2$ dimer magnets, as revealed by the unusual asymmetric lineshape of their excitations at…

Novel Ni-Co-Mn-Ti all-d-metal Heusler alloys are exciting due to large multicaloric effects combined with enhanced mechanical properties. An optimized heat treatment for a series of these compounds leads to very sharp phase transitions in…

We present an \textit{ab initio} auxiliary field quantum Monte Carlo method for studying the electronic structure of molecules, solids, and model Hamiltonians at finite temperature. The algorithm marries the \textit{ab initio} phaseless…

强关联电子 · 物理学 2018-11-13 Yuan Liu , Minsik Cho , Brenda Rubenstein

We study the electronic states of the magnetically ordered Mn3Pt alloy within the density functional theory. Mn3Pt has been believed that one third of Mn atoms have no magnetic moment in an antiferromagnetic phase (so-called the F-phase)…

材料科学 · 物理学 2009-11-13 Yohei Kota , Hiroki Tsuchiura , Akimasa Sakuma

We present a theoretical survey of ferromagnetic transition temperatures in cubic (III,Mn)V semiconductors based on a model with $S=5/2$ local moments exchange-coupled to itinerant holes in the host semiconductor valence band. Starting from…

材料科学 · 物理学 2016-08-16 T. Jungwirth , Jürgen König , Jairo Sinova , J. Kučera , A. H. MacDonald

To understand the halfmetallic ferromagnet EuB6 we use the Kondo lattice model for valence and conduction band. By means of a recently developed many-body theory we calculate the electronic properties in the ferromagnetic regime up to the…

强关联电子 · 物理学 2009-11-11 M. Kreissl , W. Nolting

Correlated electrons in a binary alloy $A_{x}B_{1-x}$ are investigated within the Hubbard model and dynamical mean--field theory (DMFT). The random energies $\epsilon_{i}$ have a bimodal probability distribution and an energy separation…

强关联电子 · 物理学 2009-11-10 Krzysztof Byczuk , Walter Hofstetter , Dieter Vollhardt
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