The yttrium iron gaet (YIG) samples are prepared at different temperatures from 900 ℃ to 1300 ℃ by the metalorganic decomposition (MOD) method.The chemical composition and crystal structure of the samples are studied by scanning electron microscope (SEM),XRD,and M(o)ssbauer spectrometer.It is shown that the ratio of ferric ions on two types of sites,the octahedral and the tetrahedral,is increased with the sintering temperature.At 1300 ℃,the pure gaet phase has been obtained,in which the ferric ions ratio is 2∶3 leading to the minimum magnetic coercivity and maximum saturation magnetization.These results provide a route to synthesize pure YIG materials as the basic materials used in various spintronics applications.