New spectroscopic results of trivalent chromium in magnesium gallate

Cr3+ centers in MgGa2O4 powder samples are investigated by excitation and emission spectroscopic measurements at 4.2, 77 and 300 K. The 2E(2G)→4A2 (4F) and 4T2(4F)→4A2(4F) electronic transitions are observed in the red and infrared regions and associated with chromium trivalent ions in octahedral sites. The results show that the material presents both high and intermediate crystal fields for these ions. The crystal-field parameter, Dq, and Racah parameters, B and C, are determined from the measurements.