Anisotropy Linebroadening in Polycrystalline V–In Substituted YIG

Polycrystalline linewidth and magnetization have been measured between 77° and 300°K at 9.2 GHz on V–In substituted YIG in the composition range $\text{0[equal to or less-than]x[equal to or less-than]1.50}$ and $\text{0[equal to or less-than]y[equal to or less-than]0.50}$ for Y_3−2xCa_2xFe_5−x−y V_xIn_yO₁₂. The linewidths were compared with theoretical values inferred from measurements of K₁ (K₂ negligible) and M_s on single crystals for $\text{0[equal to or less-than]x[equal to or less-than]0.90}$ and $\text{0[equal to or less-than]y[equal to or less-than]0.35}$ between 4° and 300°K on the basis of a recent theory by Schlömann. Data on dense, single‐phase polycrystals are in good quantitative agreement with Schlömann's theory for samples with weak anisotropy (H_a≪4πM_s, where H_a = 2 | K₁ | / M). For high anisotropy materials ${\mathrm{(H}}_a{\text{[equal to or greater-than]4πM}}_s)$ , linewidth derived from area fitting of the normalized curves follows ΔH = 0.5H_a. Moderately small (<3%) amounts of porosity yield additive linebroadening effects.