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MA: Fachverband Magnetismus

MA 52: Poster II

MA 52.33: Poster

Thursday, March 15, 2018, 15:00–18:00, Poster C

Effect of high Mn-doping on magnetocaloric La(FeSi)₁₃-based compounds — •Alexandra Terwey¹, Benedikt Eggert¹, Daniela Trienes¹, Joachim Landers¹, Soma Salamon¹, Werner Keune¹, Katharina Ollefs¹, Iliya Radulov², Konstantin Skokov², Oliver Gutfleisch², and Heiko Wende¹ — ¹Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg, Germany — ²Functional Materials, TU Darmstadt, Darmstadt, Germany

By combining low temperature Mössbauer studies with and without applied magnetic fields and magnetometry, we investigated the effect of Mn-doping with increasing concentrations on La(FeSi)₁₃-based compounds and thereby analyzed the coupling of Mn to the Fe sublattices in the system. La(FeSi)₁₃-based materials have the potential use as magnetocaloric refrigerants due to a first-order magneto-structural phase transition near room temperature when additionally doped with hydrogen. Mn doping prevents hydrogen segregation. From our Mössbauer studies at low temperatures in applied external magnetic fields we find a decrease in the hyperfine fields with increasing Mn concentration as well as an increase in the spin frustration. This increase in spin frustration points towards a stronger AFM coupling between Fe and Mn and additionally results in a lowering of the saturation magnetization and of the local Fe moment as validated by magnetometry and extracted hyperfine magnetic fields. Funding by the DFG (SPP1599) is acknowledged.