Paramagnetic Resonance Spectra of Chromium and Manganese in the Spinel Structure

Abstract

The paramagnetic resonance spectrum of ${\mathrm{Cr}}^{3+}$ was measured on the single crystal of ruby spinel Mg${\mathrm{Al}}_2$ ${\mathrm{O}}_4$ at the wavelengths of 3 cm, 1.2 cm, and 8.6 mm. The spectrum confirms that ${\mathrm{Cr}}^{3+}$ is at a $B$ site and can be described with an axial spin Hamiltonian $S=\frac{3}{2}$, $2D=0.990\pm 0.005$ ${\mathrm{cm}}^{-1\mathrm{}}$, $g_{\mathrm{II}}=1.986\mathrm{}\pm 0.001$, $g_{\perp }=1.989\mathrm{}\pm 0.002$.