Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: Poster 1
MA 19.15: Poster
Dienstag, 6. September 2022, 17:30–20:00, P2
Insights into the magnetic structure of Mn-doped La(Fe,Si)13 — •Benedikt Eggert1, Johanna Lill1, Olga N. Miroshkina1, Konstantin Skokov1, Katharina Ollefs1, Markus E. Gruner1, Oliver Gutfleisch2, and Heiko Wende1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen — 2Functional Materials, TU Darmstadt
Magnetic cooling has the potential to replace conventional gas compression refrigeration. Here, materials such as FeRh, NiMn-based Heusler alloys or La(Fe,Si)13 exhibit a sizeable first-order magnetocaloric effect To further optimize the efficiency, it is necessary to tune the phase transition close to room temperature and reduce the thermal hysteresis. For La(Fe,Si)13, it was shown that it is possible to tailor the phase transition towards room temperature by interstitial H-doping, while maintaining first-order character. In addition, Mn doping allows fine tuning of Tc to enlarge to temperature window of operation, inducing also second-order features. We discuss variations of the electronic and geometric structure in La(Fe,Si)13 with increasing Mn content by means of Mössbauer spectroscopy.
Mössbauer measurements reveal a reduction of the Fe magnetic moment with increasing Mn concentration. A reduction and
broadening of the hyperfine field distribution occurs for higher Mn-content,
while in-field measurements indicate a non-colinear spin structure for high Mn-concentrations.
We acknowledge the financial support through the Deutscheforschungsgemeinschaft wihtin the framework of the CRC/TRR270 HoMMage.