Thermal-history dependent magnetoelastic transition in (MN, FE)<sub>2</sub>(P, SI)

Conference paper (2015)

Authors

X.F. Miao RST/Radiation, Science and Technology , RST/Fundamental Aspects of Materials and Energy - AS
L. Caron RST/Radiation, Science and Technology , RST/Fundamental Aspects of Materials and Energy - AS
Z. Gercsi Imperial College London, Trinity College Dublin
A. Daoud-Aladine ISIS Neutron and Muon Source
N.H. van Dijk RST/Radiation, Science and Technology , RST/Fundamental Aspects of Materials and Energy - AS
K. G. Sandeman Imperial College London, Trinity College Dublin
E.H. Brück RST/Fundamental Aspects of Materials and Energy - AS , RST/Radiation, Science and Technology
Research Group
RST/Fundamental Aspects of Materials and Energy (AS) (TU Delft)
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Published Date

2015

Language

English

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Faculty

Applied Sciences

Department

RST/Radiation, Science and Technology

Research Group

RST/Fundamental Aspects of Materials and Energy

Abstract

(Mn, Fe)2(P, Si)-type compounds are, to date, the most promising materials for refrigeration and energy conversion applications due to the combination of highly tunable giant magnetocaloric effect (GMCE) and low material cost.[1, 2] The GMCE of these compounds originates from the first-order magnetoelastic transition around the magnetic phase-transition temperature TC. However, the phase-transition temperature shows a peculiar thermal-history dependence in these compounds. As-prepared (Mn, Fe)2(P, Si) displays a significantly lower TC upon first cooling than on second and subsequent cooling processes. Since this behavior is only observed in as-prepared samples it is called the 'virgin effect'. The difference in TC between the first and second cooling processes of the as-prepared sample, hereafter referred to as ΔTC0, is taken as a measure of how strong the virgin effect is. The virgin effect is not exclusive to (Mn, Fe)2(P, Si) compounds being observed in other GMCE materials[3, 4], however its origin was for a long time unknown. In this study, we report our high-resolution neutron diffraction experiments that finally shed light on the origin of the virgin effect. Additionally, recovery of the virgin effect induced by thermal activation was observed experimentally.