␤-Ga 2 O 3 single crystals doped with the Cr 3ϩ ion were grown in an O 2 atmosphere using the floating zone method. Electron paramagnetic resonance ͑EPR͒ spectra of the Cr 3ϩ ion were recorded with an X band EPR spectrometer at 20°C. The rotation patterns of Cr 3ϩ spectra in the crystallographic planes together with spin-Hamiltonian parameters showed unequivocally that the actual local site symmetry of the Cr 3ϩ ion in ␤-Ga 2 O 3 is not orthorhombic, as previously reported, but monoclinic. The spectroscopic splitting tensor g and the zero-field splitting parameters B k q s were determined with an effective spin Hamiltonian. The Cr 3ϩ ions replace Ga 3ϩ ions in oxygen octahedra rather than in oxygen tetrahedra. The energy levels of the ground state of a Cr 3ϩ ion embedded in the ␤-Ga 2 O 3 crystal were calculated.

Articles you may be interested inInsertion of lithium ions into TiO2 (rutile) crystals: An electron paramagnetic resonance study of the Li-associated Ti3+ small polaron J. Appl. Phys. 113, 053712 (2013); 10.1063/1.4790366Study of the ground multiplet of Kramers rare earth ions in solid matrices by multifrequency electron paramagnetic resonance spectroscopy: Nd 3 + in PbWO 4 single-crystalsThe electron paramagnetic resonance of the Eu 2ϩ ion in a PbWO 4 single crystal, grown by the Czochralski method, has been investigated using an X-band spectrometer. The rotation patterns in the crystallographic planes together with spin-Hamiltonian parameters of Eu 2ϩ show that the local site symmetry of the Eu 2ϩ ion is tetragonal. The spectroscopic splitting tensor g, zero-field splitting parameters B k q , and hyperfine tensor A are determined with the effective spin Hamiltonian. Energy levels of the ground state for Eu 2ϩ embedded in the PbWO 4 crystal are calculated. It turns out that the Eu 2ϩ ion substitutes for the Pb 2ϩ ion without any charge compensation.

Articles you may be interested inInsertion of lithium ions into TiO2 (rutile) crystals: An electron paramagnetic resonance study of the Li-associated Ti3+ small polaron J. Appl. Phys. 113, 053712 (2013); 10.1063/1.4790366Study of the ground multiplet of Kramers rare earth ions in solid matrices by multifrequency electron paramagnetic resonance spectroscopy: Nd 3 + in PbWO 4 single-crystals Lead tungstate single crystals doped with Gd 2 O 3 were grown by the Czochralski method in Ar atmosphere. The electron paramagnetic resonance of the Gd 3ϩ ion in a PbWO 4 single crystal has been investigated at 9.4 GHz. The spectroscopic splitting tensor g and zero-field splitting parameters B k q were determined using the effective spin Hamiltonian. The rotation patterns in the crystallographic planes together with spin Hamiltonian parameters of Gd 3ϩ ion show that the local site symmetry of the Gd 3ϩ ion in PbWO 4 crystal is tetragonal and that the Gd 3ϩ ion substitutes for the Pb 2ϩ ion without local charge compensation at the nearby surroundings.