Magnetic linear dichroism and features of the local magnetic structure of HoFe₃(BO₃)₄ single crystal in ⁵F₂ and ⁵F₃ 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.