Theoretical Study for Pressure Effects in Orbital Ordering Ferromagnets

Abstract

The magnetic properties of orbital ordering systems under high pressures are investigated theoretically on the basis of one-dimensional multi-band Hubbard model with exact diagonalization procedure. Pressure effects are taken into account through the change of the inter-atomic transfer and the orbital energies. It is pointed out that magnetic phase transitions can be possible with the antiferrodistortive structures being kept. It is also shown that saturation of Heisenberg-type intersite exchange coupling J_s occurs for large inter-atomic transfer energy t in high-spin state.