Electron Paramagnetic Resonance ofMn2+in KTaO3

Abstract

The electron paramagnetic resonance of ${\mathrm{Mn}}^{2+}$ in KTa${\mathrm{O}}_3$ was measured over a temperature range 4-110 K. At 77 K, the spin-Hamiltonian constants are $g_{\parallel }=2.\mathrm{}000\pm 0.001$, $g_{\perp }=2.\mathrm{}000\pm 0.001$, $D=+0.\mathrm{}147\pm 0.003$ ${\mathrm{cm}}^{-1\mathrm{}}$, $A_{\parallel }=-(86.5\mathrm{}\pm 0.5)\times {10}^{-4\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $A_{\perp }=-(84\mathrm{}\pm 1.5)\times {10}^{-4\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$. The results indicate that the ${\mathrm{Mn}}^{2+}$ is substitutional at a ${\mathrm{Ta}}^{5+}$ site with an adjacent oxygen vacancy. The temperature dependence of $D$ is correlated with the soft-mode frequency of the host. The quadrupole splitting $Q^{\prime }=+(0.\mathrm{}8\pm 0.1)\times {10}^{-4\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ was determined from the forbidden hyperfine transitions.