Substitution of gadolinium, aluminium, and indium in yttrium calcium vanadium garnets

The effect of Gd, In, and Al substitution on magnetic and resonance properties in the system {Y 3-2x-a Ca 2x Gd a } [Fe 2-z In z ]- (Fe 3-x-y V x Al y )O 12 is reported for 0.5 \leq x \leq 0.9, 0 \leq a \leq 1.1, 0 \leq y \leq 0.8 , and z = 0, 0.5 . It is shown that compositions exist in this system that display improvements over conventional garnets in this respect to temperature stability and X -band resonance linewidth. The series Y 3-2x Ca 2x Fe 4.75-x V x In 0.25 O 12 is suggested as one such optimal series of compositions.