Reaction sintering of dense gadolinium-iron garnet (GdIG) material

Two synthesis methods of gadolinium-iron garnet (GdIG) materials were described. The first one was a typical co-precipitation-calcination method (CP method). In the second one gadolinium-iron perovskite (GdIP, GdFeO3) and iron oxide (alpha-Fe2O3) were mixed in proper amounts for GdIG stoichiometry (RS method). DSC data for precursor powder mixtures obtained from both synthesis routes allowed to examine heat effects. In the case of the CP method, two crucial reactions were observed. The first one at ab. 767 degrees C was associated with the formation of GdIP phase, whereas the second one at ab. 1080 degrees C was attributed to GdIG formation. For the RS method, only formation of GdIG at 1122 degrees C was observed. Both powder mixtures were sintered at 1200, 1300, and 1400 degrees C for 2 h. For the CP method, the highest density was below 90 % even at 1400 degrees C whereas for the RS method the density of materials sintered at the same temperature exceeded 97 %.

Automated summary

Two synthesis methods of gadolinium-iron garnet (GdIG) materials were described in the study, with the CP method showing two crucial reactions at different temperatures and the RS method only observing the formation of GdIG. The density of materials sintered at 1400 degrees C for the RS method exceeded 97%, while for the CP method, the highest density was below 90% even at the same temperature.