La_(1-x)Sr_xFeO_3纳米微粉的微结构与磁性  

Microstructure and magnetic properties of La_(1-x)Sr_x FeO_3 nanopowders

作　　者：寇昕莉[1] 秦勇[1] 何海英[1] 李建功[1] 

机构地区：[1]兰州大学材料科学与工程研究所,甘肃兰州730000

出　　处：《材料科学与工艺》2004年第2期140-143,共4页Materials Science and Technology

基　　金：国家自然科学基金资助项目(59773039).

摘　　要：为了研究La1-xSrxFeO3纳米微粉的成分及颗粒尺寸对其微结构及磁学性能的影响,采用溶胶-凝胶法制备了不同颗粒尺寸、不同Sr含量的钙钛矿型La1-xSrxFeO3(x=0～0 3)纳米微粉,采用X射线衍射和振动样品磁强计对其结构与磁性进行了分析.分析表明,所制样品均具有正交钙钛矿结构;对于颗粒尺寸相近、Sr含量不同的样品,随Sr含量增加,晶格收缩;在具有不同颗粒尺寸的La1-xSrxFeO3(x=0 3)纳米微粉中,随着颗粒尺寸的减小,晶格膨胀;La1-xSrxFeO3(x=0～0 3)纳米微粒具有弱铁磁性,Sr含量的增加导致自发磁化强度下降,且随着颗粒尺寸的减小,La1-xSrxFeO3(x=0 3)纳米微粉的自发磁化强度增大;由Sr的替代以及颗粒尺寸减小引起的结构变化导致磁性的变化.In order to investigate the effects of Sr content and particle size on the microstructure and magnetic properties of La_(1-x)Sr_xFeO_3 nanopowders, perovskite-type La_(1-x)Sr_x FeO_3 (x=0～0.3) nanopowders with different particle sizes were prepared by using sol-gel method. Structure and magnetic properties were analyzed by XRD and VSM. All the samples prepared are single-phase orthorhombic perovskites. Structure analysis shows that the cell volume of La_(1-x)Sr_x FeO_3 (x=0～0.3) nanopowders with nearly the same particle size decreases with increasing content of Sr. For La_(1-x)Sr_x FeO_3 (x=0.3) nanoparticles with different particles sizes, the decreasing particle size leads to the lattice expansion. Magnetic measurement suggests the existence of weak ferromagnetism in the prepared samples. The spontaneous magnetization decreases with increasing content of Sr and increasing particle size. The effect of microstructure on magnetic properties is discussed.

关 键 词：复合铁氧体 溶胶-凝胶法 磁性 La1-xSrxFeO3纳米微粉 微结构 

分 类 号：TB383[一般工业技术—材料科学与工程]