Crystal-Field Levels of Sm3+ Ion in Low-Dimensional Magnetic Cu3Sm(SeO3)2O2Cl

The transmission spectra of a two-dimensional frustrated magnetic Cu3Sm(SeO3)2O2Cl were measured in the region of f–f -transitions of the Sm3+ ion in a wide temperature range (4–300 K). The energies of 40 crystal-field levels of the Sm3+ ion are determined for the ground and excited multiplets in the spectral region of 2000–10 000 cm–1. The spectra revealed two magnetic phase transitions: at temperature of TN = 35 K, magnetic ordering occurs, and at temperature of TR = 8.5 K—spin-reorientation transition. The ground Kramers doublet of the Sm3+ ion splits only at a low-temperature phase transition. The data obtained on the energy states of the ground multiplet 6H5/2 of the Sm3+ ion are used to calculate the contribution of samarium to the heat capacity of Cu3Sm(SeO3)2O2Cl.