【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.更多还原

【Abstract】 In order to investigate the effects of Sr content and particle size on the microstructure and magnetic properties of La_1-xSr_xFeO₃ nanopowders, perovskite-type La_1-xSr_x FeO₃ （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-xSr_x FeO₃ （x=0～0.3） nanopowders with nearly the same particle size decreases with increasing content of Sr. For La_1-xSr_x FeO₃ （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.更多还原