Optical and magneto-optical spectra and electron structure of ErAl₃(BO₃)₄single crystal

Linearly polarized absorption spectra and magnetic circular dichroism (MCD) spectra of ErAl₃(BO₃)₄single crystal were measured in the range of 10000–27000 cm⁻¹at 90 K. The Stark components of the ground and excited multiplets of Er³⁺ion were identified in terms of the irreducible representations, basing on the linearly polarized absorption spectra. MCD spectra permitted us to measure the Zeeman splitting of some transitions and so to determine changes of the Landé factors along the C₃axis during these transitions. Additionally, the MCD spectra permitted us to identify some states in the |J,±M_J) function approximation. In particular, it was shown that the ground state of the Er³⁺ion in this approximation has M_J= ± 13/2 that corresponds to magnetic moment m = ±7.8 μ_B. Very intensive f-f vibronic transitions, corresponding to electron transitions from the upper components of the ground multiplet, were revealed. Energies of the local vibrations in a number of the excited states were found.