The magnetization of most magnetic materials decreases monotonically with increasing temperature. In this work, we found that the temperature coefficient of magnetization of Mn4-xGaxC alloys can be tuned from negative values to positive values by controlling the composition x. The antiperovskite-type Mn4-xGaxC (0.05≤x≤0.75) alloys were prepared by using induction melting method, which is more efficient in large-scale production and obtaining full-density alloys in comparison with the traditional solid-state-reaction method. The values of the temperature coefficient of magnetization of Mn4-xGaxC change continuously from negative to positive with decreasing x. The Mn4-xGaxC alloys with highly thermal-stable magnetization is expected to present in the composition range of 0.15<x<0.25. The saturation magnetization of Mn4-xGaxC increases with increasing x, owing to the reduced number of antiferromagnetically coupled Mn atoms at the cubic corner with the face-centered Mn atoms. Most Mn4-xGaxC alloys with varying x display near-zero remanent magnetization and coercivity at room temperature. The Currie temperature of Mn4-xGaxC decreases with increasing x. The x-ray photoelectron spectra of Mn 2p, Ga 2p, and C 1 s reveal distinct splitting due to the diverse chemical states of these atoms at different lattice positions and/or phases. Our work has developed a class of alloys capable of offering a desired temperature coefficient of magnetization across a broad temperature range, thereby offering a method to manipulate the thermodynamics of magnetization.
