钙钛矿锰氧化物Nd_(0.5)Sr_(0.3)Ba_(0.2)MnO_3多晶的磁性和相分离  

Magnetic Properties and Phase Separation of Perovskite Manganites Nd_(0.5)Sr_(0.3)Ba_(0.2)MnO_3 Polycrystalline

作　　者：赵建军[1] 鲁毅[1] 邢茹[1] 浩斯巴雅尔[1] 金香[1] 郑琳[1] 

机构地区：[1]包头师范学院物理系,内蒙古包头014030

出　　处：《内蒙古师范大学学报（自然科学汉文版）》2009年第1期48-51,共4页Journal of Inner Mongolia Normal University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(50672126);内蒙古自然科学基金资助项目(200607010102)

摘　　要：通过固相反应法合成Nd0.5Sr0.3Ba0.2MnO3多晶样品,采用粉末X射线衍射(XRD)、超导量子磁强计(SQUID)和电子自旋共振谱仪(ESR),对样品的结构和磁性进行了研究.XRD检测结果表明,样品为单相,空间群为Pbnm.磁性测量和ESR结果表明,在降温过程中,样品经历了铁磁有序转变(TC=250 K)、电荷有序转变(TCO=190 K)和反铁磁转变(TN=120 K).通过ESR谱线的参数随温度的变化可以观察到各个磁有序转变温度,TN<T<TCO时,线宽ΔHpp的变化可用极化子跳跃模型来解释,而g因子的增大是由于随着温度的降低,体系的轨道有序逐渐增强所致.Polycrystalline sample Nd0.5Sr0.3Ba0.2MnO3 was prepared by conventional solid state reaction method. The structure and magnetic properties have been studied with X-ray diffraction patterns, SQUID and ESR. The sample is in single phase with the space group Pbnm symmetry. With the decrease of temperature, Nd0.5Sr0.3Ba0.2MnO3 undergoes a ferromagnetic transition at TC = 250 K, a charge-ordering at TCO= 190 K and an antiferromagnetic transition at TN = 120 K. When TN〈T〈 TCO, the linewidth shows large decrease with the increase of temperature and it is attributed to the hoping of the Jahn-Teller polarons. The g-value increases continuously with decreasing temperature in the paramagnetic state,suggesting a gradual strengthening of the orbital ordering.

关 键 词：钙钛矿锰氧化物 相分离 电子自旋共振 电荷有序 

分 类 号：O482.52[理学—固体物理]