Double magnetocaloric peak feature observed in quaternary Ni-Mn-In based Heusler alloys

¹ Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
² Department of Physics, Southern Illinois University, Carbondale, USA
³ Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg, Luxembourg

^* e-mail: rodionov@physics.msu.ru

Published online: 4 July 2018

Abstract

We present the results of the studies of magnetic and magnetocaloric (MCE) properties of quaternary Heusler alloys Ni_48.5Mn₃₅In₁₅Co_1.5 and Ni₅₀Mn₃₅In_13.5Al_1.5 in temperature range between 80 K and 400 K. While doping initial ternary Ni-Mn-In alloy with 1.5 at.% Al does not change T_C^A as well as M_S, doping with 1.5 at.% Co significantly increases both T_C^A and M_S. The direct magnetocaloric measurements around martensitic transition and austenite Curie temperature reveal the competition between the contributions of different signs. The latter is related to the vicinity of transition temperatures of austenite and martensite, resulting in mixed state, where both phases undergo magnetic order-disorder transformation in the same temperature region. Additionally temperature dependencies of adiabatic temperature change ΔT_ad and magnetic entropy ΔS_M of the system exhibit additional peak feature which we attribute to intermartensitic transition occurring in these alloys.