Ferrimagnets with ising ions, phase H-T-x diagrams for holmium-yttrium iron garnets

The magnetization of holmium-yttrium iron garnet crystals Hosub(x)Ysub(3-x)Fesub(5)Osub(12) is measured in magnetic fields up to 300 kOe, at helium to nitrogen temperatures and for concentrations x varying between 0.25 and 1.63. The experimental H-T-x diagrams are plotted. The magnetic phase transformations in the system as a function of H, T, and x are investigated theoretically for three orientations of the magnetic field H parallel <111>, H parallel <110> and H parallel <001> on the basis of the Ising model for Ho3+ ions. The theoretical and experimental results are compared. The possible causes of some of the discrepancies are discussed