Magnetism and Magnetocaloric Properties of Mn3Zn1-xSnxC and Mn3-xCrxZnC Compounds

Upon substitution of Sn for Zn, the Curie temperature of Mn3ZnC is lowered from 380 to 375 K for Mn3Zn0.95Sn0.05C and to 305 K for Mn3Zn0.75Sn0.25C. In accordance with the second-order ferromagnetic-paramagnetic transition, a room-temperature magnetocaloric effect without thermal and magnetic hysteresis is observed over a wide temperature range. The maximum value of the magnetic-entropy change ΔSM for a magnetic-field change from 0 to 5 T is 2.42 J·kg−1 ·K−1 at 386 K for Mn3Zn0.95Sn0.05C and 1.70 J·kg−1 ·K−1 at 308 K for Mn3Zn0.75Sn0.25C. Meanwhile, substitution of Cr for Mn lowers the temperature of ferromagnetic-ferrimagnetic transition from 233 K for Mn3ZnC to 230 K for Mn2.9Cr0.1ZnC and to 175 K for Mn2.1Cr0.9ZnC. An inverse magnetocaloric effect with ΔSM equal to 0.28 J·kg−1 ·K−1 at 223 K for a field change from 0 to 1.47 T is observed for Mn2.9Cr0.1 ZnC.