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

Abstract

We present the results of the studies of magnetic and magnetocaloric (MCE) properties of quaternary Heusler alloys Ni48.5Mn35In15Co1.5 and Ni50Mn35In13.5Al1.5 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 TCA as well as MS, doping with 1.5 at.% Co significantly increases both TCA and MS. 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 ΔTad and magnetic entropy ΔSM of the system exhibit additional peak feature which we attribute to intermartensitic transition occurring in these alloys.