Disordered local moment state of magnetic transition metals: a self-consistent KKR CPA calculation

Pindor, A J; Staunton, J. B.; Stocks, G. M.; Winter, H.

doi:10.1088/0305-4608/13/5/012

Cited by 235 publications

(89 citation statements)

References 12 publications

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“…We simulate the hightemperature paramagnetic (PM) phase of CMO using the disordered local moments [27][28][29][30][31][32][33][34][35][36] approach where the magnetic disorder is modeled by randomly distributed collinear magnetic moments. In our case this entails initiating the simulations with Mn magnetic moments distributed in a special quasirandom (SQS) sense [37] where an equal number of atoms is given up and down spins.…”

Section: Methodsmentioning

confidence: 99%

Nature of the octahedral tilting phase transitions in perovskites: A case study of CaMnO3

Klarbring

Simak

2018

Phys. Rev. B

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The temperature-induced antiferrodistortive (AFD) structural phase transitions in CaMnO 3 , a typical perovskite oxide, are studied using first-principles density functional theory calculations. These transitions are caused by tilting of the MnO 6 octahedra that are related to unstable phonon modes in the high-symmetry cubic perovskite phase. Transitions due to octahedral tilting in perovskites normally are believed to fit into the standard soft-mode picture of displacive phase transitions. We calculate phonon-dispersion relations and potential-energy landscapes as functions of the unstable phonon modes and argue based on the results that the phase transitions are better described as being of order-disorder type. This means that the cubic phase emerges as a dynamical average when the system hops between local minima on the potential-energy surface. We then perform ab initio molecular dynamics simulations and find explicit evidence of the order-disorder dynamics in the system. Our conclusions are expected to be valid for other perovskite oxides, and we finally suggest how to predict the nature (displacive or order-disorder) of the AFD phase transitions in any perovskite system.

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Section: Methodsmentioning

confidence: 99%

Nature of the octahedral tilting phase transitions in perovskites: A case study of CaMnO3

Klarbring

Simak

2018

Phys. Rev. B

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“…The Perdew-Burke-Ernzerhof exchange-correlation approximation [21] gave a good description of the lattice parameters and magnetic moments. The paramagnetic phase was modeled within the coherent potential approximation [22] combined with the disordered local moment [23,24] approach. This approximation accurately describes the paramagnetic state with randomly oriented local magnetic moments [23].…”

Section: Electronic Structure Calculationsmentioning

confidence: 99%

“…The paramagnetic phase was modeled within the coherent potential approximation [22] combined with the disordered local moment [23,24] approach. This approximation accurately describes the paramagnetic state with randomly oriented local magnetic moments [23]. Here, the AlFe 2 B 2 ternary system was treated as a quaternary Al(Fe ↑ 0.5 Fe ↓ 0.5 ) 2 B 2 alloy, with a random mixture of two magnetic states of Fe.…”

Section: Electronic Structure Calculationsmentioning

confidence: 99%

Mössbauer study of the magnetocaloric compound AlFe2 B 2

et al. 2016

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The crystal and magnetic structures of AlFe 2 B 2 have been studied with a combination of X-ray and neutron diffraction and electronic structure calculations. The magnetic and magnetocaloric properties have been investigated by magnetisation measurements. The samples have been produced using high temperature synthesis and subsequent heat treatments. The compound crystallises in the orthorhombic crystal system Cmmm and it orders ferromagnetically at 285 K through a second order phase transition. At temperatures below the magnetic transition the magnetic moments align along the crystallographic a-axis. The magnetic entropy change from 0 to 800 kA/m was found to be -1.3 J/K kg at the magnetic transition temperature.

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“…Refs. [38,39]). Nevertheless, also in these KKR-CPA calculations, all the magnetic moments of the Mo atoms converged to zero values.…”

Section: Magnetism and Relativistic Effectsmentioning

confidence: 99%

Effect of the tetragonal distortion on the electronic structure, phonons and superconductivity in the Mo3Sb7 superconductor

Wiendlocha

Sternik

2014

Intermetallics

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Effect of tetragonal distortion on the electronic structure, dynamical properties and superconductivity in Mo3Sb7 is analyzed using first principles electronic structure and phonon calculations. Rigid muffin tin approximation (RMTA) and McMillan formulas are used to calculate the electron-phonon coupling constant λ and superconducting critical temperature. Our results show, that tetragonal distortion has small, but beneficial effect on superconductivity, slightly increasing λ, and the conclusion that the electron-phonon mechanism is responsible for the superconductivity in Mo3Sb7 is supported. The spin-polarized calculations for the ordered (ferromagnetic or antiferromagnetic), as well as disordered (disordered local moment) magnetic states yielded non-magnetic ground state. We point out that due to its experimentally observed magnetic properties the tetragonal Mo3Sb7 might be treated as noncentrosymmetric superconductor, which could have influence for the pairing symmetry. In this context the relativistic band structure is calculated and spin-orbit interaction effects are discussed.

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Disordered local moment state of magnetic transition metals: a self-consistent KKR CPA calculation

Cited by 235 publications

References 12 publications

Nature of the octahedral tilting phase transitions in perovskites: A case study of CaMnO3

Nature of the octahedral tilting phase transitions in perovskites: A case study of CaMnO3

Mössbauer study of the magnetocaloric compound AlFe2 B 2

Effect of the tetragonal distortion on the electronic structure, phonons and superconductivity in the Mo3Sb7 superconductor

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