Local field fluctuations in the substituted aluminum iron garnets, Y<inf>3</inf>Fe<inf>5-x</inf>Al<inf>x</inf>O<inf>12</inf>

Abstract

The saturation magnetizations and the Mossbauer spectrums of substituted aluminum iron garnets, Y3Fe5-xAlxO12, at room temperature are reported. It is seen that the saturation magnetizations initially decreases in a linear manner as Al3+replaces the Fe3+and then deviates from the linearity as more Fe is replaced. The hyperfine fields for the 'a' site Fe ions are seen to decrease as the Al content increases, while the hyperfine fields for the 'd' site Fe ions shows no changes at the initial doping levels. The half width of the lines in the Mossbauer sextets for the 'a' site ions is seen to increase with the increase in the Al content. This broadening is interpreted as being due to the local fluctuations arising at these sites from the increasing disorder occurring in the 'd' sub-lattice as more Al is added. © 1999 Elsevier Science Ltd.