Electron-spin-resonance study of manganese-doped spinel

An electron-spin-resonance study of manganese-doped synthetic spinel samples (Mg${\mathrm{Al}}_2$ ${\mathrm{O}}_4$) produced spectra with six sharp main lines corresponding to the hyperfine components of the $M_s=\frac{1}{2}\leftrightarrow M_s=-\frac{1}{2}$ transitions with the coupling constant $A=83\mathrm{}$ G, ten sharp forbidden transitions, and a broad background arising from the effect of the $D$ tensor on the other four $M_s\leftrightarrow M_{}^{\prime }{}_s{}^{}$ transitions. The measured value of $D_{\mathrm{expt}}$ equal to 64 G was explained in terms of the Goodenough model using the Orbach et al. method.