Optical spectroscopy of low-dimensional rare-earth iron borates

The family of RFe3(BO3)4 borates (R=Pr, Nd, Eu-Er, Y) was studied by high-resolution optical absorption and Raman spectroscopies. Structural and magnetic phase transitions were detected and the types of magnetic structure were determined. Energy of crystal-field (CF) levels and exchange splitting of the ground state of the R3+ ion were obtained from the analysis of optical spectra. CF calculations were carried out. Effective magnetic field at the R3+ site was found, using the calculated value of the magnetic g-factor. Some peculiarities of modeling the paramagnetic susceptibility of NdFe3(BO3)4 are discussed.