Direct measurements of the magnetocaloric effect in ribbon samples of Heusler alloys Ni - Mn - M (M = In, Sn)

TL;DR

This study directly measures the magnetocaloric effect in rapidly quenched Ni-Mn-based Heusler alloy ribbons, revealing both direct and inverse effects linked to magnetic and structural phase transitions, relevant for magnetic refrigeration.

Contribution

It introduces a precise measurement method for the magnetocaloric effect in ribbon samples and reports new findings on phase transition-related effects.

Findings

Both direct and inverse magnetocaloric effects observed.

Inverse effects occur near ferromagnetic transitions.

Magnetocaloric effects linked to magnetic and structural transitions.

Abstract

Direct measurements of the magnetocaloric effect in samples of rapidly quenched ribbons of Mn50Ni40In10 and Ni50Mn37Sn13 Heusler alloys, with potential applications in magnetic refrigeration technology, are carried out. The measurements were made by a precise method based on the measurement of the oscillation amplitude of the temperature in the sample while is subjected to a modulated magnetic field. In the studied compositions both direct and inverse magnetocaloric effects associated with magnetic (paramagnet - ferromagnet - antiferromagnet) and structural (austenite - martensite) phase transitions are found. Additional inverse magnetocaloric effects of small value are observed around the ferromagnetic transitions.