Tunable room-temperature zero temperature coefficient of resistivity in antiperovskite compounds Ga1−xCFe3 and Ga1−yAlyCFe3

The effects of the Ga content and the substitution of Al for Ga on the temperature coefficient of resistivity (TCR) of antiperovskite GaCFe3 have been investigated systematically. Our results indicate the value of TCR and its temperature range can be tuned by altering chemical compositions. With decreasing the Ga content in Ga1−xCFe3 or increasing Al dopant in Ga1−yAlyCFe3, the sign of TCR changes from positive to negative and room-temperature zero TCR material can be achieved. Typically, the optimized TCR values are about −5.72 ppm/K(265–315 K) and −14.68 ppm/K(280–320 K) for Ga0.95CFe3 and Ga0.85Al0.15CFe3, respectively. The possible mechanisms for the observed low TCR are discussed.