CoFe_2O_4纳米颗粒的结构、磁性以及离子迁移  

Structure, magnetic properties and atomic immigration of CoFe_2O_4 nanoparticles

作　　者：王丽[1] 王海波[1] 王涛[1] 李发伸[1] 

机构地区：[1]兰州大学磁学与磁性材料教育部重点实验室,兰州730000

出　　处：《物理学报》2006年第12期6515-6521,共7页Acta Physica Sinica

摘　　要：聚乙烯醇(PVA)溶胶凝胶法制备出CoFe2O4纳米微粉,用X射线衍射研究了铁氧体纳米颗粒的结构.测量了CoFe2O4纳米颗粒80—873K的变温穆斯堡尔谱,发现纳米颗粒的磁转变温度范围为793—813K,比块体材料的磁性转变温度要低.CoFe2O4纳米颗粒的德拜温度θA=674K,θB=243K,比块体材料要小.CoFe2O4纳米颗粒超精细场Hf随温度的变化符合T3/2+T5/2定理.当温度较高时,平均同质异能移IS随温度的升高而减小,并呈线性关系.CoFe2O4 nanoparticles have been prepared by sol-gel method. Mǒssbauer spectra at temperature varying from 80 to 873 K showed that the atomic site preference of nanoparticles is different from that of the bulk material. The results also showed that the To of nanosized CoFe2O4 is much lower than that of the bulk counterpart. This decrease of Tc in the nanoparticles may be attributed to the redistribution of Fe and Co cations at the A and B sites. The Mǒssbauer spectra also revealed that the hyperfine field varied with the temperature and the hyperfine interaction follows T3/2 ＋ T5：2 law approximately. The average isomer shift decreases almost linearly with increasing temperature.

关 键 词：纳米颗粒 磁性 穆斯堡尔谱 

分 类 号：O482[理学—固体物理]