Ab-initio Based Analytical Evaluation of Entropy in Magnetocaloric Materials with First Order Phase Transitions
| Autor: | Vittorio Basso, Marco Piazzi, Jan Zemen |
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| Rok vydání: | 2015 |
| Předmět: |
Phase transition
magnetocaloric effect Ab initio Thermodynamics FOS: Physical sciences 02 engineering and technology Physics and Astronomy(all) 01 natural sciences electronic entropy 0103 physical sciences Magnetic refrigeration 010306 general physics Electronic entropy Density Functional Theory Physics Condensed Matter - Materials Science Condensed matter physics Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology First order cond-mat.mtrl-sci Materials science Antiperovskite Mean field theory Density functional theory 0210 nano-technology first order magnetic transitions Mn-based antiperovskites |
| Zdroj: | Physics Procedia. 75:1332-1344 |
| ISSN: | 1875-3892 |
| DOI: | 10.1016/j.phpro.2015.12.149 |
| Popis: | 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 |
| Databáze: | OpenAIRE |
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