Magnetic Properties of (Fe1-xMnx)2AlB2 and the Impact of Substitution on the Magnetocaloric Effect

Published

August 6, 2020

Author(s)

D. Potashnikov, Elad Nisan NMN Caspi, A. Pesach, S. Kota, M. Sokol, L. A. Hanner, M. W. Barsoum, Hayden Evans, A. Eyal, A. Keren, O. Rivin

Abstract

In this work, we investigate the magnetic structures of (Fe_1−xMn_x)₂AlB₂ solid-solution quaternaries in the x = 0 to 1 range using X-ray and neutron diffraction, magnetization measurements, and mean field theory calculations. While Fe₂AlB₂ and Mn₂AlB₂ are known to be ferromagnetic (FM) and antiferromagnetic (AFM), respectively, herein we focused on the magnetic structure of their solid solutions, which is not well understood. The FM ground state of Fe₂AlB₂ becomes a canted AFM at x approximately equal} 0.2, with a monotonously diminishing FM component until x approximately equal} 0.5. The FM transition temperature (T_C) decreases linearly with increasing x. These changes in magnetic moments and structures are reflected in anomalous expansions of the lattice parameters, indicating strong magneto-elastic coupling. Lastly, the magnetocaloric properties of the solid solutions were explored. For x = 0.2 the isothermal entropy change (δS_m) is smaller by 30% than it is for Fe₂AlB₂, while the relative cooling power is larger by 6%, due to broadening of the temperature range of the transition.

Citation

Physical Review Materials

Volume

4

Issue

8

Pub Type

Journals

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Keywords

Neutron diffraction

Citation

Potashnikov, D. , Caspi, E. , Pesach, A. , Kota, S. , Sokol, M. , Hanner, L. , Barsoum, M. , Evans, H. , Eyal, A. , Keren, A. and Rivin, O. (2020), Magnetic Properties of (Fe_1-xMn_x)₂AlB₂ and the Impact of Substitution on the Magnetocaloric Effect, Physical Review Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930371 (Accessed September 13, 2024)