文献类型：期刊文献

英文题名：Effect of high pressure on Moessbauer spectra of NiFe2O4 ultrafine particles with different grain sizes

作者：Ma, Y.G.[1]; Jin, M.Z.[1]; Liu, M.L.[1]; Chen, G.[1]; Sui, Y.[2]; Tian, Y.[3]; Zhang, G.J.[4]; Jia, Y.Q.[4]

机构：[1] Analysis Test Center, Jilin University, 130023, Changchun, China; [2] Shenyang Institute of Metal Research, Academia Sinica, 110015, Shenyang, China; [3] Lucky Star High Technology Group Co., 130021, Changchun, China; [4] Department of Chemistry, E. China Univ. Sci. Technol., 200237, Shanghai, China

年份：2000

卷号：65

期号：1

起止页码：79

外文期刊名：Materials Chemistry and Physics

收录：EI(收录号：2000285187453)

语种：英文

外文关键词：Grain size and shape - High pressure effects - Magnetic relaxation - Mossbauer spectroscopy - Nickel compounds - Superparamagnetism - Synthesis (chemical)

摘要：The nickel ferrite ultrafine powders with different grain sizes (8, 12.20, 40 and 80 nm) have been synthesized. Moessbauer spectra of 57Fe nucleus in the samples composed of the nickel ferrite ultrafine powder before and after the high pressure treatments have been measured. The superparamagnetic relaxation is markedly suppressed by high pressure. The intensity of the sextets in Moessbauer spectra increases with increasing the grain size or pressure. The effect of high pressure on Moessbauer spectra of the samples may involve not only the physical changes, but also the chemical or structural ones in the ultrafine particles during the high pressure treatment, such as the formation of the interfacial region between the ultrafine particles and the rearrangements of the atoms in the surface layers of the ultrafine particles.