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

Detailed analyses of spectroscopic and temperature-dependent magnetic susceptibility data are reported for the crystal-field split energy levels of the FJ and D4 of Tb 3+ in stoichiometric single crystals of ortho-aluminate TbAlO3. The spectroscopic data include absorption spectra obtained between 2940 and 480 nm from 8 to 300K. High resolution fluorescence spectra are reported, representing transitions from D4 to F6,5,4, at a sample temperature of 85K. Using crystal-field modeling techniques recently adapted for low symmetry systems, we have assigned all 58 experimental Stark levels within the FJ and D4 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 TbAlO3 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 F6 multiplet manifold. r 2007 Elsevier B.V. All rights reserved.