Computer Simulation of Temperature and Field Dependences of Sublattice Magnetizations and Spin-Flip Transition in Gallium-Substituted Yttrium Iron Garnet

On the basis of the molecular field model, sublattice magnetizations in gallium-substituted yttrium iron garnet Y 3 Ga x Fe 5- x O 12 are calculated over a wide range of x , temperature and applied magnetic field with a computer program. Comparing the calculated temperature dependence of spontaneous magnetization, the critical fields of the spin-flip transition at high magnetic fields and the ferrimagnetic Curie temperature, with experimental data, the super-exchange coefficients in YIG and Y 3 Ga x Fe 5- x O 12 were evaluated.