Spectroscopic and magnetic susceptibility analyses of the 7F J and 5D 4 energy levels of Tb 3+(4f 8) in TbAlO 3

Abstract

Detailed analyses of spectroscopic and temperature-dependent magnetic susceptibility data are reported for the crystal-field split energy levels of the 7F J and 5D 4 of Tb 3+ in stoichiometric single crystals of ortho-aluminate TbAlO 3. The spectroscopic data include absorption spectra obtained between 2940 and 480 nm from 8 to 300 K. High resolution fluorescence spectra are reported, representing transitions from 5D 4 to 7F 6,5,4, at a sample temperature of 85 K. Using crystal-field modeling techniques recently adapted for low symmetry systems, we have assigned all 58 experimental Stark levels within the 7F J and 5D 4 manifolds, with a fitting standard deviation of 4.5 cm −1 (3.8 cm −1 rms error). As a further test, the theoretical Stark levels and calculated wavefunctions were used to determine the temperature dependence of the magnetic susceptibility along the c-axis of the TbAlO 3 crystal. Good agreement is obtained between the calculated susceptibility and temperature-dependent magnetic data reported earlier, including a prediction of a 0.2 cm −1 splitting of the ground-state quasi-doublet. The susceptibility calculation also confirms the predicted ordering of states within the 7F 6 multiplet manifold.