Preparation, infrared and magnetic susceptibility studies of LnB3O6 (Ln=Gd, Eu and Sm)

The rare-earth borates of composition LnB 3 O 6 (Ln=Sm, Eu and Gd) have been prepared and their infrared and magnetic susceptibility were studied. The infrared spectra show the characteristic bands due to planar BO 3 and tetrahedral BO 4 units. The DC susceptibilities were measured from 5 to 300 K. The electron paramagnetic resonance (EPR) spectrum for Gd 3+ was recorded at room temperature. The EuB 3 O 6 and SmB 3 O 6 show van Vleck paramagnetism, corresponding to the ground state 7 F 0 of Eu 3+ and 6 H 5/2 of Sm 3+ , respectively. From the susceptibility data of EuB 3 O 6 and SmB 3 O 6 , spin–orbit coupling constants of 348 and 458 cm −1 were obtained for Eu 3+ and Sm 3+ , respectively. The magnetic susceptibility of GdB 3 O 6 follows the Curie law. From the EPR measurement the g value of Gd 3+ in GdB 3 O 6 is found to be 2.01. Both the EPR measurements and magnetic susceptibility results agree well and show that Gd 3+ ion in this compound is scarcely affected by the crystal field.