Crystal field and exchange interactions in the SmFe3(BO 3)4 multiferroic

Abstract

The optical spectra of oriented SmFe3(BO3) 4 single crystals are studied in the region of the f-f transitions in the Sm3+ ion by Fourier spectroscopy. The energies, the symmetry properties, and the exchange splittings of the Stark sublevels of the ground and 17 excited multiplets of the Sm3+ ion in a crystal field of symmetry D 3 are determined from the measured temperature dependences of polarized-radiation absorption spectra. The parameters of the crystal field acting on samarium ions and the parameters of the exchange interaction between Sm3+ and Fe3+ ions are found. The anisotropy of the effective exchange interaction is shown to be substantially stronger than the magnetic anisotropy, due to a strong crystal-field-induced mixing of the ground and excited multiplets. © 2014 Pleiades Publishing, Inc.