ANNEALING DEPENDENCE OF MAGNETIC-PROPERTIES IN NANOSTRUCTURED PARTICLES OF YTTRIUM-IRON-GARNET PREPARED BY CITRATE GEL PROCESS

Yttrium iron garnet (YIG) particles were first synthesized using a low -temperature method based on the citrate gel process. The annealing te mperature dependence of the magnetic behaviour was investigated by mea ns of transmission Fe-57 Mossbauer spectrometry and DC magnetic measur ements. The as-prepared particles behaves as an amorphous-like structu re. Annealing treatments cause aggregation and crystallization of part icles. For low annealing temperatures, one can suggest a nanostructure d behaviour of the YIG particles, which progressively disappears when the annealing temperature increases. Depending on the annealing temper ature, YIG nanostructured particles of different size, in the range 50 -700 nm were obtained. The values of the saturation magnetization as w ell as the Curie temperature for the YIG particles are close to those observed for well-crystallized YIG.