Magnetic circular dichroism and absorption spectra of [formula omitted] transition in HoAl3(BO3)4 and HoFe3(BO3)4 single crystals

Abstract

Comparative study of magnetic circular dichroism (MCD) and absorption spectra of HoAl3(BO3)4 and HoFe3(BO3)4 single crystals in the region of I85→F55 transition of the Ho3+ ion was carried out. Absorption spectra were decomposed into the Lorentz shape components and intensities of transitions were obtained. Unusually strong vibronic transitions were observed in HoAl3(BO3)4, but were not observed in HoFe3(BO3)4 that testified to the strong non diagonal vibronic interaction in HoAl3(BO3)4. The MCD spectra were analyzed in approximation of the |J,±MJ〉 wave functions of the free atom and using concept of the crystal quantum number. Peculiarity of application of this concept to ions with integer moments was revealed and modification of the concept was suggested. With the help of the MCD spectra, the Zeeman splitting of some transitions was found. In particular, the Landé factor gC≈2 of the ground state of the Ho3+ ion in HoAl3(BO3)4 in the trigonal axis direction was determined. It appeared to be five times less than that in HoFe3(BO3)4 also found with the help of the MCD.