Scaling of the isothermal entropy change and magnetoresistance in Ni-Mn-In based off-stoichiometric Heusler alloys

Magnetic and Superconducting Materials Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, India

^a e-mail: vishnusharma@rrcat.gov.in

Received: 27 June 2012
Revised: 6 November 2012
Accepted: 25 January 2013
Published online: 11 June 2013

Abstract

We show that for identical changes in magnetic field, the temperature dependence of the change in isothermal entropy across the martensite-austenite phase transition in different Ni-Mn-In based off-stoichiometric Heusler alloys scales to a single curve. The temperature dependence of magnetoresistance across the same martensite-austenite phase transition in these alloys also scales to follow a similar curve. The temperatures corresponding to the peak value of the isothermal entropy change and the peak magnetoresistance for a particular applied magnetic field are correlated with distinct features observed in the magnetization vs. temperature and resistivity vs. temperature curves respectively of these alloys (in the same magnetic field). These findings can be utilized in estimating the useful temperature regime for the isothermal entropy change and magnetoresistance of Ni-Mn-In based alloys with newer compositions, and to predict the magnitude of these functionalities, without performing actual experiments.