Effect of gadolinium and manganese on the physical properties of yttrium iron garnet

The Y3-xGdxFe5-yMnyO12 (x = y = 0.0, 0.2, 0.4, 0.6, 1.0, and 1.5) powders were synthesized by a co-precipitation method. The structural analysis confirmed the presence of the cubic structure of YIG, the formation of the secondary phase YFeO3 and the stoichiometry proposed for Y3-xGdxFe5-yMnyO12. The results of the FTIR spectroscopy show three prominent absorption bands that shift to lower wavenumber values with the increase of codopant concentrations. Energy bandgap values are found to be 2.96 eV for pure YIG and 3.02 +/- 0.1 eV for doped powders. Photoluminescence spectra show that all the samples exhibit intense peaks around 530 nm. Moreover, Gd3+ and Mn2+ partial alternatives strongly influence the magnetic behavior of YIG nanoparticles. It is observed that coercivity is affected by the crystallite size of 0.0 <= x = y <= 0.6, confirming the multidomain nature of the powders, which could be acceptable in microwave applications and data storage uses.