Structural phase transition of cubic ferromagnetic materials

Abstract

The interplay between the structural and the magnetic phase transitions in cubic ferromagnetic materials with narrow d-bands is studied using the two-band Hubbard Hamiltonian. Expanding the free energy in terms of the magnetization and the strain, we obtain phase diagrams for the structural and the magnetic transitions. It is shown that under suitable conditions, ferromagnetic materials can go through a structural transition from a cubic to a tetragonal structure. The present results explain the experimental data on the structural transition in ferromagnetic Fe100-xPtx materials.