New spectroscopic results of trivalent chromium in magnesium gallate

Abstract Cr 3+ centers in MgGa 2 O 4 powder samples are investigated by excitation and emission spectroscopic measurements at 4.2, 77 and 300 K. The 2 E( 2 G)→ 4 A 2 ( 4 F) and 4 T 2 ( 4 F)→ 4 A 2 ( 4 F) 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.