Element-Resolved Thermodynamics of Magnetocaloric ${\mathrm{LaFe}}_{13\ensuremath{-}x}{\mathrm{Si}}_{x}$

Element-Resolved Thermodynamics of Magnetocaloric ${LaFe}_{13 - x} {Si}_{x}$

M. E. Gruner, W. Keune, B. Roldan Cuenya, C. Weis, J. Landers, S. I. Makarov, D. Klar, M. Y. Hu, E. E. Alp, J. Zhao, M. Krautz, O. Gutfleisch, and H. Wende

Phys. Rev. Lett. 114, 057202 – Published 4 February 2015

Abstract

By combination of two independent approaches, nuclear resonant inelastic x-ray scattering and first-principles calculations in the framework of density functional theory, we demonstrate significant changes in the element-resolved vibrational density of states across the first-order transition from the ferromagnetic low temperature to the paramagnetic high temperature phase of ${LaFe}_{13 - x} {Si}_{x}$ . These changes originate from the itinerant electron metamagnetism associated with Fe and lead to a pronounced magneto-elastic softening despite the large volume decrease at the transition. The increase in lattice entropy associated with the Fe subsystem is significant and contributes cooperatively with the magnetic and electronic entropy changes to the excellent magneto- and barocaloric properties.

Received 19 August 2014

DOI:https://doi.org/10.1103/PhysRevLett.114.057202

Authors & Affiliations

M. E. Gruner^1,2,*, W. Keune^1,3, B. Roldan Cuenya⁴, C. Weis¹, J. Landers¹, S. I. Makarov^1,3, D. Klar¹, M. Y. Hu⁵, E. E. Alp⁵, J. Zhao⁵, M. Krautz², O. Gutfleisch⁶, and H. Wende¹

¹Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
²IFW Dresden P.O. Box 270116, 01171 Dresden, Germany
³Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
⁴Department of Physics, Ruhr-University Bochum, 44780 Bochum, Germany
⁵Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
⁶Materials Science, TU Darmstadt, 64287 Darmstadt, Germany