La_(0.5-x)Nd_xSr_(0.5)CoO_3(x=0,0.1)氧化物的结构和磁性  

Structure and Magnetic Properties of La_(0.5-x)Nd_xSr_(0.5)CoO_3 (x=0,0.1) Manganites

作　　者：王洪金[1] 吴洪业 赵建军[1] 邢茹[1] 何利民[1] 鲁毅[1] 

机构地区：[1]包头师范学院物理科学与技术学院,内蒙古包头014030

出　　处：《稀土》2014年第4期84-87,共4页Chinese Rare Earths

摘　　要：采用固相反应法制备了La0.5-xNdxSr0.5CoO3(x=0,0.1)多晶样品。通过XRD和SQUID研究了样品的结构和磁性。研究表明,随着Nd3+的掺入使体系中由于晶格畸变引起的电子-声子耦合减弱,会使Co3+—O—Co4+之间的双交换作用增强,使样品的居里温度提高了30 K;从磁化强度随温度变化曲线可以看出x=0.1样品的ZFC曲线形成的峰明显比x=0样品ZFC曲线的峰尖。这是由于随温度的升高Nd3+离子间4f电子的间接交换作用减弱,导致自旋的非共线结构贡献减少,使材料的磁化强度迅速增加引起的。在TC附近样品都出现了明显的顺磁-铁磁转变,样品形成的是短程的铁磁有序。Polycrystal samples of La0.5-xNdxSr0.5CoO3（x=0,0.1） were prepared by solid state reaction method. The structure and magnetic properties of such samples were characterized by XRD and SQUID, respectively. Experimental results indicate that structural distortion with increasing concentration of Nd^3＋ weakens the electron - phonon coupling and enhances double exchange interactions via Co^3＋ - O - Co^4＋ , and increase the Curie temperature by 30 K. It is found in the temperature dependence of magnetization curve that the peak appearing in the ZFC curve of the x = 0.1 sample is sharper than that of the undoped one. This is attributed to the weakened indiect exchange interactions between the 4f electrons of Nd3 ~ with increasing temperature, which decreases the contribution from the noncollinear spin structure, and rapidly increases the magnetization. Pa- ramagnetism - ferromagnetism transitions appear in both samples and ferromagnetic order is of short - range nature.

关 键 词：晶场畸变 结构 磁性 双交换作用 

分 类 号：O482.52[理学—固体物理] O614.33[理学—物理]