TY  - JOUR
AU  - Mendive Tapia, Eduardo
AU  - Neugebauer, Jörg
AU  - Hickel, Tilmann
TI  - Ab initio calculation of the magnetic Gibbs free energy of materials using magnetically constrained supercells
JO  - Physical review / B
VL  - 105
IS  - 6
SN  - 1098-0121
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2022-01662
SP  - 064425
PY  - 2022
AB  - We present a first-principles approach for the computation of the magnetic Gibbs free energy of materials using magnetically constrained supercell calculations. Our approach is based on an adiabatic approximation of slowly varying local moment orientations, the so-called finite-temperature disordered local moment picture. It describes magnetic phase transitions and how electronic and/or magnetostructural mechanisms generate a discontinuous (first-order) character. We demonstrate that the statistical mechanics of the local moment orientations can be described by an affordable number of supercell calculations containing noncollinear magnetic configurations. The applicability of our approach is illustrated by firstly studying the ferromagnetic state in bcc Fe. We then investigate the temperature-dependent properties of a triangular antiferromagnetic state stabilizing in two antiperovskite systems Mn3AN (A=Ga, Ni). Our calculations provide the negative thermal expansion of these materials as well as the ab initio origin of the discontinuous character of the phase transitions, electronic and/or magnetostructural, in good agreement with experiment.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000761174500003
DO  - DOI:10.1103/PhysRevB.105.064425
UR  - https://juser.fz-juelich.de/record/906740
ER  -