Kinetic arrest of the ferromagnetic state in Mn sub(3) GaC and Ni sub(2) MnGa composite mixtures

Abstract

The kinetics of the ferromagnetic to antiferromagnetic transition in Mn sub(3) GaC can be arrested and its magnetic properties can be tuned by mixing a small amount (approx. 10 percent) of Heusler Ni sub(2) MnGa to Mn sub(3) GaC. A detailed study of magnetic properties of composite mixtures of Mn sub(3) GaC and Ni sub(2) MnGa with different antiperovskite to Heusler ratio, reveals that the ferromagnetic Ni sub(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.