Eu3+ luminescence in La5Si2BO13 with apatite related structure and magnetic studies in Ln5Si2BO13 (Ln=Gd, Dy)

Eu3+ photoluminescence is studied in La5Si2BO13 with apatite related structure. La5−xEuxSi2BO13 [x=0.05, 0.1, 0.3, 0.5, 0.7, 1.0, 2.0] compositions are synthesized. The emission results shows that Eu3+ ions occupy two different cationic sites viz., La(1) and La(2). The increase in the intensity of 5D0–7F0 line with increasing Eu3+ content shows the preferential occupancy of Eu3+ in La(2) site due to the existence of short La(2)–O(4) (free oxide ion) bond. The observation of antiferromagnetic interactions in Gd and Dy analogues supports the structural features elucidates from photoluminescence studies.

In La5Si2BO13, the La(1)O9 polyhedra share faces, the La(2)O7 polyhedra are connected through corners and La(2)O7 and La(1)O9 polyhedra are connected to each other by edge sharing along ‘z’-axis.Figure optionsDownload as PowerPoint slide