Mn-based antiperovskite functional materials： Review of research

Our recent research on the Mn-based antiperovskite functional materials AXMn3 （A： metal or semiconducting elements; X： C or N） is outlined. Antiperovskite carbides （e.g., AlCMn3） show large magnetocaloric effect comparable to those of typical magnetic refrigerant materials. Enhanced giant magnetoresistance up to 70% at 50 kOe （1 Oe=79.5775 A.m-1） over a wide temperature span was obtained in Ga1-xZnxCMn3 and GaCMn3 xNix. In Cu0.3Sn0.5NMn3.2, negative thermal expansion （NTE） was achieved in a wide temperature region covering room temperature （α = -6.8 ppm/K, 150 K-40 K）. Neutron pair distribution function analysis suggests the Cu/Sn-Mn bond fluctuation is the driving force for the NTE in Cu1- xSnxNMn3. In CuN1- xCxMn3 and CuNMn3 yCoy, the temperature coefficient of resistivity （TCR） decreases monotonically from positive to negative as Co or C content increases. TCR is extremely low when the composition approaches the critical points. For example, TCR is - 1.29 ppm/K between 240 K and 320 K in CuN0.95C0 05Mn3, which is one twentieth of that in the typical low-TCR materials （- 25 ppm/K）. By studying the critical scaling behavior and X deficiency effect, some clues of localized-electron magnetism have been found against the background of electronic itinerant magnetism.