Magnetocaloric behavior and magnetic ordering in MnPdGa
| Autor: | Ram Seshadri, Daniil A. Kitchaev, Yuzki M. Oey, Joshua D. Bocarsly, Joya A. Cooley, Emily C. Schueller |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Magnetic structure Condensed matter physics 02 engineering and technology Electronic structure 021001 nanoscience & nanotechnology Coupling (probability) 01 natural sciences Ferromagnetism 0103 physical sciences Magnetic refrigeration Curie temperature Antiferromagnetism General Materials Science 010306 general physics 0210 nano-technology Ground state |
| Zdroj: | Physical Review Materials, vol 5, iss 1 |
| Popis: | MnPdGa, a compound crystallizing in the ${\mathrm{Ni}}_{2}\mathrm{In}$ structure, is a material displaying magnetic ordering near room temperature and is a potential ambient-temperature magnetocaloric. Screening based on electronic structure calculations suggest that MnPdGa may exhibit a high magnetocaloric figure of merit due to its strong magnetostructural coupling. Here we report the preparation of MnPdGa and employ high--resolution synchrotron x-ray diffraction to confirm its hexagonal ${\mathrm{Ni}}_{2}\mathrm{In}$-type structure. The zero-field ground state is shown to be a conical spin-wave state, defined by a long-range modulation of the conventional conical antiferromagnet structure. Near the Curie temperature, the measurements carried out here coupled with electronic structure calculations suggest that a fully ferromagnetic state can form at elevated temperatures under an applied field. A peak magnetocaloric entropy change $\mathrm{\ensuremath{\Delta}}{S}_{M}=\ensuremath{-}3.54\phantom{\rule{0.28em}{0ex}}\mathrm{J}\phantom{\rule{0.28em}{0ex}}{\mathrm{kg}}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ ($30.1\phantom{\rule{0.16em}{0ex}}\mathrm{mJ}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$) is measured at ${T}_{C}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}315\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ at an applied field $H=5\phantom{\rule{0.16em}{0ex}}\mathrm{T}$. The exchange-driven, nontrivial magnetic structure found in MnPdGa is compared with the somewhat better-studied MnPtGa on the basis of electronic structure calculations. |
| Databáze: | OpenAIRE |
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