Synthesis of mono and multidomain YIG particles by chemical coprecipitation or ceramic procedure

Abstract

Yttrium iron garnet powders have been synthesized by chemical coprecipitation using two different precursors, nitrates and chlorides, and by an oxides mixture route. It is shown that depending on the precursors and synthesis conditions used pure yttrium iron garnet powders can be obtained with a mono or multidomain magnetic behaviour. The yttrium iron garnet crystalline structure, as studied by Raman spectroscopy, was already formed after calcination at temperatures as low as 800 °C when the nitrate precursors were used. However, calcination temperatures of up to 1100 °C were required to obtain yttrium iron garnet powders when the precursors were chlorides or when the oxides mixture route was chosen. The saturation magnetization of the powders correlates well with the structural characterization: when nitrate precursors were used, the saturation magnetization was already close to the bulk value, 26.8 emu/cm3, after calcination at 800 °C. However, the saturation magnetization of the powders obtained by the chlorides and oxides mixture routes was close to zero up to calcination temperatures of 1100 °C. Finally, both the chlorides and the oxides mixture routes yield multidomain micron sized yttrium iron garnet powders, whereas the nitrates route led to monodomain submicron sized powders.