Magnetocaloric effect manipulated through interchain exchange coupling in nanochain arrays

Abstract

Magnetocaloric effect in nanochain arrays is numerically studied when interchain exchange couplings (Jinter) are taken into account. With increasing Jinter, moment-reorientation phase transition temperature driven by anisotropy is enhanced and magnetic ordering phase transitions governed by Jinter may happen independently at higher temperatures, resulting in temperature induced multiple phase transitions that separate distinct dynamic properties of magnetization. As a result, maximum values of positive and negative magnetic entropy change (ΔSM) are both close to 0.4 J kg−1 K−1, with their peak temperature 100–300 K and 250–550 K, depending on Jinter, and a large refrigeration capacity is obtained due to a wide working temperature range of ΔSM. In nanostructures, the proper magnetic viscosity arising from Jinter makes materials become semi-bulk, i.e., in which ΔSM maximum value and peak temperature are highly enhanced, associated with a considerably wide working temperature range.