Gallium-Substituted Yttrium Iron Garnet

Spontaneous moments, near 0^∘{}K, of specimens with x to 3.00 in the system Y₃Fe_5-xGaₓO₁₂ have been measured and the ionic distribution determined by means of the model given previously by Geller, Williams, Espinosa, and Sherwood. It is shown that although for x to about 2.75, the preference of Ga³⁺ ions for tetrahedral sites is greater than that of Al³⁺ ions in the analogous system Y₃Fe_5-xAlₓO₁₂, for greater x, the preference of Ga³⁺ ions for tetrahedral sites may be the same as or less than that of Al³⁺ ions. The Ga³⁺ ion distribution in this system is such that to x≈2.50, the garnets act like ideal N\'eel ferrimagnets. Comparisons are made with the results of other investigations on this system.