Ab-initio based analytical evaluation of entropy in magnetocaloric materials with first order phase transitions

Abstract

We combine spin polarised density functional theory and thermodynamic mean field theory to describe the phase transitions of antiperovskite manganese nitrides. We find that the inclusion of the localized spin contribution to the entropy, evaluated through mean field theory, lowers the transition temperatures. Furthermore, we show that the electronic entropy leads to first order phase transitions in agreement with experiments whereas the localized spin contribution adds second order character to the transition. We compare our predictions to available experimental data to assess the validity of the assumptions underpinning our multilevel modelling.

PDFLaTeX, 10 pages, 4 figures, 2 tables, accepted for publication in Physics Procedia as ICM 2015 Conference Proceeding

References in corpus (3)

• Fluctuating local moments, itinerant electrons and the magnetocaloric effect: the compositional hypersensitivity of FeRh
• Element-resolved thermodynamics of magnetocaloric LaFe${}_{13-x}$Si${}_x$
• First-principles calculation of the instability leading to giant inverse magnetocaloric efects