Magnetic properties of the Ising ferromagnetic iron nitride system

The magnetic properties of a mixed spin-32 and spin-1 Ising ferromagnetic system on an expanded FCC lattice in Fe4N are studied. In particular, the expanded FCC lattice was divided into one simple cubic lattice and three inhomogeneous simple cubic lattices in Monte Carlo simulations. We investigate the effect of the next-nearest atom and the nitrogen atom on the phase diagrams and critical behavior, in order to clarify the characteristic magnetic features observed in Fe4N. The magnetization, internal energy and specific heat curve and the phase diagrams are given. We found that the transition temperature and magnetic moment increase with the increase of the exchange interaction of next-nearest atomic and the exchange interaction between Fe (II) (at the face-centered one) via nitrogen atomic. It is because of the exchange interaction due to the nitrogen atom that Fe4N has a higher saturation magnetization than pure iron.