Room-temperature magnetocaloric effect in Fe-substituted CoCr2O4 spinels

Abstract

In this study, structural, magnetic and magnetocaloric properties of Co(Cr1−xFex)2O4 (x = 0.0, 0.25, 0.50, 0.75 and 1.0) cubic spinel compounds produced by solgel method were investigated. The cubic crystal structure of CoCr2O4 has not disrupted by Fe substitution, but the lattice parameter increases with increasing Fe content due to bigger ionic radii of Fe3+ ions than Cr3+ ions. The magnetic transition temperature of CoCr2O4 (96 K) is increased to 312 K when 50% Fe is substituted with Cr in CoCr2O4 structure. The maximum magnetic entropy change values are − 0.88 J/kgK, − 1.27 J/kgK and − 1.39 J/kgK under 7 T magnetic field for x = 0.0, 0.25 and 0.5 in Co(Cr1−xFex)2O4, respectively. The relative cooling power values are enhanced × 5 when 50% Fe3+ ions are substituted with Cr3+ ions in CoCr2O4. Therefore, the CoFeCrO4 sample might be a potential material for magnetic refrigerant applications due to its considerable high magnetization values, having room-temperature magnetic transition temperature, highest magnetic entropy change and relative cooling power compared to other samples.