Polarized laser selective excitation and electron paramagnetic resonance of Er3+ centers in SrLaAlO4 crystals

The crystal growth and optical and magnetic spectroscopies of perovskite phase, strontium lanthanium aluminate (SrLaAlO4) doped with trivalent erbium are reported. Electron paramagnetic resonance of SrLaAlO4:1%Er3+ identifies two distinct Er3+ ion centers in this material: a tetragonal (C4v) symmetry center with spin Hamiltonian parameters of g=2.70.05 and g=8.50.05 and a minor center of orthorhombic symmetry having gx=9.40.05, gy=6.80.05, and gz=2.30.05. From a combination of optical absorption and polarized laser selective excitation, a total of 40 energy levels and their irreducible representation symmetry labels have been determined for the C4v symmetry center, while 22 energy levels have been determined for a minor center. A C4v symmetry, crystal-field parametrization for the dominant center yields optimized parameters consistent with proposed structural models. The g tensors of the ground-state Kramers doublets, calculated from the C4v center wave functions, are in good agreement with the measured g values.