Anisotropy of Gadolinium Iron Garnet

Abstract
The ``one‐ion'' theory of origin of anisotropy has been tested by comparing the calculated value of the gadolinium contribution to the anisotropy of GdIG at 0°K with experimental measurements. Crystal field, dipolar, and dipole—crystal field effects are included in the calculation. The median of the values obtained using the crystal field parameters for Gd3+ in four diamagnetic garnets agrees within 3% with the result of torque measurements on a pure GdIG crystal. The experimental value, −21.9×104 ergs/cc, is approximately 10% lower than previous values for the anisotropy of GdIG. The good agreement between the calculated and experimental anisotropies provides quantitative confirmation of the theory used in the calculations.