Kinetic arrest of the ferromagnetic state in Mn[Formula: see text]GaC and Ni[Formula: see text]MnGa composite mixtures.

The kinetics of the ferromagnetic to antiferromagnetic transition in Mn $$_3$$ GaC can be arrested and its magnetic properties can be tuned by mixing a small amount ( $$\sim $$ 10%) of Heusler Ni $$_2$$ MnGa to Mn $$_3$$ GaC. A detailed study of magnetic properties of composite mixtures of Mn $$_3$$ GaC and Ni $$_2$$ MnGa with different antiperovskite to Heusler ratio, reveals that the ferromagnetic Ni $$_2$$ MnGa polarizes magnetic spins of the antiperovskite phase by creating a magnetic strain field in its vicinity. The Heusler phase acts as a defect centre whose influence on the magnetic properties of the majority antiperovskite phase progressively diminishes, creating a distribution of transition temperatures. Such strong interaction between the two phases of the mixture allows for tunability and control over the properties of such magneto-structurally transforming materials.