Color center formation in vacuum sintered Nd3xY3-3xAl5O12 transparent ceramics

Color center formation was studied in vacuum sintered Nd3xY3-3xAl5O12 transparent ceramics. The primary color centers were F- and F+-centers as evidenced by optical absorption in the 250-400 nm wavelength range and the presence of an electron spin resonance (ESR) line at g = 1.9977. Annealing in air at 1600 degrees C for 10 h reduced the number of color centers to below the detection limit of ESR. Color center formation is controlled by oxidation and reduction of Fe2+/(3+) impurities. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3549872]