Magnetic linear dichroism and features of the local magnetic structure of HoFe3(BO3)4 single crystal in 5 F 2 and 5 F 3 excited states of Ho3+ ion

We measured spectra of magnetic linear dichroism (MLD) of ⁵I₈ → ⁵F₂, ⁵F₃ transitions in the basal plane of the HoFe₃(BO₃)₄ single crystal in the light propagated along the trigonal c-axis at temperature 2 K as a function of magnetic field 0 – 65 kOe directed along a and b axes. The substantial anisotropy of the MLD in the basal plane was revealed. The anisotropy of the MLD is strongly different for different electron transitions, that is, the MLD is mainly connected with the excited electron states. Transformations of the MLD spectra permitted us to retrace variations of the Ho ion magnetic moment orientation in different excited electron states as a function of the magnetic field. It was shown that in the excited states the local Ho magnetic moments do not reveal reorientation transitions synchronously with that of the Fe-sublattice. A small splitting of the ground doublet of the Ho³⁺ ion was observed during certain electron transitions. This means that during these electron transitions the local crystal field can change not only in the excited but in the ground state as well.