Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Caloric effects in ferromagnetic materials
MA 35.4: Vortrag
Mittwoch, 3. April 2019, 15:45–16:00, H52
Element-specific view on La(FeSi)13 — •Katharina Ollefs1, Markus E. Gruner1, Alexandra Terwey1, Benedikt Eggert1, Iliya Radulov2, Konstantin Skokov2, Werner Keune1, Fabrice Wilhelm3, Andrei Rogalev3, Oliver Gutfleisch2, and Heiko Wende1 — 1Faculty of Physics and CENIDE, University of Duisburg- Essen, Germany — 2Functional Materials, Technical University Darmstadt, Darmstadt, Germany — 3Synchrotron Radiation Facility, Grenoble, France
Due to its large magneto-caloric effect, the itinerant electron metamagnet La(FeSi)13 is of great interest for its potential use in solid state refrigeration. In order to better understand the magnetic interactions in this material and how they change at the transition, we have performed x-ray absorption measurements. X-ray magnetic circular dichroism measurements in the low temperature phase at the Fe K-edge and La L2,3-edges reveal not only a magnetic moment on Fe but also a sizable magnetic moment in the 5d states of La. Magneto-optical sum-rule analysis and DFT calculations indicate an anti-parallel alignement of the Fe and La spin moment and a small orbital moment on La also anti-parallel to spin moment. Disentangling the different magnetic moment contributions in La(FeSi)13 may reveal additional sources for hysteresis and might shed light on the thermodynamic role of the particular magnetic degrees of freedom. Funding by the DFG (SPP1599) is acknowledged.