Luminescence is a spontaneous emission of radiation from an electronically excited species not in thermal equilibrium with its environment. Luminescent materials can absorb energy and then emit that energy as photons of light [1]. This is known as excitation and emission. Luminescent materials are composed of a different matrix and an activator (usually transition element or lanthanide). Many different classes of materials can be used as matrices, including perovskites, pyrochlores, spinels, etc. WIn our experiment we are using MgAl2O4 spinel material as a matrix. While many different lanthanide ions, like Eu3+ [2], Ho3+ [3], have already been doped into the magnesium aluminate structure, there is no work regarding the Sm3+ substitution for this spinel. In this work, we investigated the possible Sm3+ ions doping into the MgAl2O4 system.
MgAl2O4 spinel was prepared by sol-gel polyacrylamide synthesis route. As this method uses acrylamide, which during the polymerization reaction forms a polymer carcass, restricting the growth of the particles. We have prepared phase pure MgAl2O4 compounds in the broad temperature range from 700 °C up to 1200 °C with relatively short annealing time of 2 h. When we tried the doping of small concentration of Sm3+ ions, there was a formation of MgO as an impurity phase. The final compounds were analyzed by different techniques, including X-ray diffraction, scanning electron microscopy (SEM) FT-IR spectroscopy. SEM results showed that with the increasing temperature the particle size increased. FTIR graphs showed the formation of spinel structure as well as that at the lower temperature (700 °C), there were additional peaks which could possibly be for Mg-O-C due to incomplete combustion.