Fotoluminescência em amostras policristalinas de galato de magnésio dopado com Ni2

The photoluminescence of MgGasO4:Ni2+ are presented in this article. The observed bands are attributed to the 1T2 (1D) ® 3T2 (3F) and 1T2 (1D) ® 3T1 (3F) spin-forbidden transitions and located in the visible and infrared regions, respectively. Absorption spectra obtained from diffuse reflectance measurements show bands associated with 3A2 (3F) ® 3T1 (3F) and 3A2 (3F) ® 3T2 (3F) transitions and a weak structure assigned to 3A2 (3F) ® 1E (1D) transition. All the observed transitions are identified with energy levels of Ni2+ in octahedral sites of magnesium gallate. From the Tanabe-Sugano energy diagrams for a d8 configuration, the crystal field Dq and interelectronic repulsion B and C parameters were calculated. We also present, for comparison, previous results of Cr3+ (d3 electronic configuration), Fe3+ (d5) and Co2+ (d7) ions in this host lattice for samples prepared with the same ceramic method.