Analysis of Phase Transitions in La and Nd Substituted YIG with Magnetic Disaccommodation Measurement

Abstract

The magnetic disaccommodation on polycrystalline Nd doped YIG NdxY3-xFe5O12 (0<x<2.5) and La doped YIG LaxY3-xFe5O12 (0<x<0.7) is studied in this work. A different behaviour with the sintering atmosphere and the dopant has been observed. For Nd doped garnets sintered in air the characteristic peak of disaccommodation in YIG shifts from 120 K to 100 K; for x=2.0 an additional 300 K peak is observed, due to the presence of magnetite in the sample, thus indicating that phase transition has been reached. In CO2 sintered samples, the process at 120 K exhibit magnetic accommodation features and the phase transition takes place at a lower doping rate. On the contrary, CO2 sintered La doped samples do not show magnetic accommodation as Nd doped YIG, but normal disaccommodation processes, with the solubility limit observed at x=0.3, whereas in air sintered samples the phase transition is not observed with disaccommodation measurements.