Structural, magnetic, electrical transport properties, and reversible room-temperature magnetocaloric effect in antipervoskite compound AlCMn3

Abstract

We report the structural, magnetic, electrical transport properties, and magnetocaloric effect (MCE) of antipervoskite compound AlCMn3. It exhibits a second-order ferromagnetic–paramagnetic phase transition around (TC) 287 K. The electronic resistivity (ρ) shows a good metallic behavior except for a slope change around TC. At lower temperatures (below 130 K), ρ∝T2 indicates that the electron-electron scatterings domain. At evaluated temperatures (130–270 K), ρ is linear dependence on temperature, implying that the phonon scatterings boost up greatly. Furthermore, a broad distribution of the magnetic entropy change (−ΔSM) peak is found to about 100 K with the magnetic field change ΔH=45 kOe. The relative cooling power are ∼137 J/kg and ∼328 J/kg (or ∼68 K2 and ∼162 K2) with ΔH=20 kOe and 45 kOe, respectively. All these values are comparable with the typical MCE associated with a second-order transition. It suggests that AlCMn3 may be considered as a candidate material for near room-temperature magnetic refrigeration because of: (i) the large full width at half peak of the −ΔSM-T curve, (ii) no hysteresis losses, (iii) the near room-temperature working temperature, and (iv) the low-cost and innoxious raw materials. Moreover, it is found that the simple theoretical model which only considering the magnetoelastic and magnetoelectronic couplings couldn’t account well for the observed MCE in antiperovskite AlCMn3.