TY - JOUR A1 - Mendive-Tapia, E. A1 - Neugebauer, J. A1 - Hickel, Tilmann T1 - Ab initio calculation of the magnetic Gibbs free energy of materials using magnetically constrained supercells N2 - We present a first-principles approach for the computation of the magnetic Gibbs free energy ofmaterials 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. KW - Ab initio KW - Thermodynamics KW - Magnetic alloys KW - Phase transformations PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543710 DO - https://doi.org/10.1103/PhysRevB.105.064425 SN - 2469-9969 VL - 105 IS - 6 SP - 1 EP - 6 PB - American Institute of Physics CY - Woodbury, NY AN - OPUS4-54371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -