Green luminescence and EPR studies on Mn-activated yttrium aluminum garnet phosphor

Yttrium aluminum garnet (Y3Al5O12) and Mn activated Y3Al5O12 phosphors have been prepared by urea combustion route in less than 5 min. The phosphors are well characterized by powder X-ray diffraction, Scanning electron microscopy and Fourier-transform infrared spectroscopic techniques. Photoluminescence tests on the pure Y3Al5O12 showed a strong green emission at 525 nm (2.36 eV) attributed to the strongly allowed transition of F+ center whereas in Mn2+ activated YAG the green emission at 519 nm is due to the T-4(1) (G)->(6)A(1) (S) transition of Mn2+ ions. EPR studies have been carried out on Mn2+ activated Y3Al5O12 phosphor at 300 and 110 K. From EPR spectra the spin-Hamiltonian parameters have been evaluated. The magnitude of the hyperfine splitting (A) indicates that the Mn2+ ions are in a moderately ionic environment. The spin concentration (N) and paramagnetic susceptibility (chi) have been evaluated and discussed.