Magnetic properties and room-temperature magnetocaloric effect in the doped antipervoskite compounds Ga 1− xAl xCMn 3 (0≤ x≤0.15)

Abstract

We report the effects of Al doping on the structure, magnetic properties, and magnetocaloric effect of antiperovskite compounds Ga 1− x Al x CMn 3 (0≤ x≤0.15). Partial substitutions of Al for Ga enhance the Curie temperature (from 250 K for x=0.0 to 312 K for x=0.15) and the saturation magnetization. On increasing the doping level x, the maximum values of the magnetic entropy change (−Δ S M ) decreases while the temperature span of −Δ S M vs. T plot broadens. Furthermore, the relative cooling power (RCP) is also studied. For 20 kOe, the RCP value tends to saturate at a high doping level (for x=0.12, 119 J/kg at 296 K). However, at 45 kOe, the RCP value increases quickly with increasing x (for x=0.15, 293 J/kg at 312 K). Considering the relatively large RCP and inexpensive raw materials, Ga 1− x Al x CMn 3 may be alternative candidates for room-temperature magnetic refrigeration.