Magnetic properties and room-temperature magnetocaloric effect in the doped antipervoskite compounds Ga1−xAlxCMn3 (0≤x≤0.15)

We report the effects of Al doping on the structure, magnetic properties, and magnetocaloric effect of antiperovskite compounds Ga1−xAlxCMn3 (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 (−ΔSM) decreases while the temperature span of −ΔSM 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, Ga1−xAlxCMn3 may be alternative candidates for room-temperature magnetic refrigeration.

► We studied the evolvement of the structure and magnetic properties of antiperovskite compounds Ga1-xAlxCMn3 as a function of the Al content.
► The FM-PM transition temperature was enhanced from 250K for GaCMn3 to 312K for Ga0.85Al0.15CMn3, which is meaningful to the room-temperature magnetocaloric effect (MCE).
► The MCE and the relative cooling power (RCP) were improved. For 20kOe, the value of RCP tends to saturation at high doping level (for x=0.12, 119J/kg at 296K).
► However, for 45kOe, the value of RCP increases quickly with increasing x (for x=0.15, 293J/kg at 312K).
► Our results indicated that the antiperovskite compounds Ga1-xAlxCMn3 may be potential room-temperature magnetic refrigerant materials.