Linewidth Reduction through Indium Substitution in Calcium-Vanadium Garnets

On the garnets ${\mathrm{Y}}_{\text{3−2x}}{\mathrm{Ca}}_{\text{2x}}{\mathrm{Fe}}_{\text{5−x−y}}{\mathrm{V}}_x{\mathrm{In}}_y{\mathrm{O}}_{12}$ , with $\text{x\hspace{0.17em}≤\hspace{0.17em}1.5}$ and $\text{y\hspace{0.17em}≤\hspace{0.17em}0.5}$ , we have measured the polycrystalline linewidth ${\mathrm{\Delta H}}_{\mathrm{poly}}$ at X‐band and room temperature and have determined from single crystals the first‐order anisotropy constant, $K_1$ . Since the single‐crystal linewidth of these materials is but a few oersteds and the polycrystalline samples had less than 1% porosity and second phase, the observed ${\mathrm{\Delta H}}_{\mathrm{poly}}$ is attributed to anisotropy broadening, according to Schlömann. The introduction of indium reduces both ${\mathrm{|\hspace{0.17em}K}}_1\mathrm{\hspace{0.17em}|}$ and ${\mathrm{\Delta H}}_{\mathrm{poly}}$ , for example: $$\begin{array}{ccccc}\text{x\hspace{0.17em}=\hspace{0.17em}0.63}& \text{y\hspace{0.17em}=\hspace{0.17em}0}& T_{\mathrm{C}}\text{\hspace{0.17em}=\hspace{0.17em}280°}\mathrm{C}& {\text{4πM}}_s\text{\hspace{0.17em}=\hspace{0.17em}650\hspace{0.17em}}\mathrm{G}& {\mathrm{\Delta H}}_{\mathrm{poly}}\text{\hspace{0.17em}=\hspace{0.17em}98\hspace{0.17em}}\mathrm{Oe}\\ \text{x\hspace{0.17em}=\hspace{0.17em}0.80}& \text{y\hspace{0.17em}=\hspace{0.17em}0.50}& T_{\mathrm{C}}\text{\hspace{0.17em}=\hspace{0.17em}155°}\mathrm{C}& {\text{4πM}}_s\text{\hspace{0.17em}=\hspace{0.17em}750\hspace{0.17em}}\mathrm{G}& {\mathrm{\Delta H}}_{\mathrm{poly}}\text{\hspace{0.17em}=\hspace{0.17em}8\hspace{0.17em}}\mathrm{Oe}\end{array}$$ . That last value is the lowest yet reported in the range of $\mathrm{T\hspace{0.17em}\approx \hspace{0.17em}}\frac{2}{3}{\mathrm{\hspace{0.17em}T}}_{\mathrm{C}}$ .