Electron Spin Resonance ofMo5+in Rutile

Abstract

The electron-spin-resonance spectrum of ${\mathrm{Mo}}^{5+}$ in the host lattice of Ti${\mathrm{O}}_2$ was determined. Both the hyperfine lines due to the coupling with Mo nuclei, and the superhyperfine lines due to the coupling with the next nearest neighbors, Ti nuclei, were observed. The sign of the $g$ factor of ${\mathrm{Mo}}^{5+}$ was found to be positive by observing the resonance with circularly polarized microwave radiation. The theory of Bleaney and O'Brien cannot be applied in this case, probably because the crystalline field is not strong enough and/or covalent bonding is appreciable.