【摘要】 采用固态反应法合成了Ｚｎ替代的Ｌａ２／３Ｃａ１／３（Ｍｎ１－ｘＺｎｘ）Ｏ３（ｘ＝０，０．１５）体系，分别测量了其零场和１特斯拉磁场下的电阻温度关系以及１１３Ｋ温度下磁阻率与磁场的关系．实验发现，在Ｌａ２／３Ｃａ１／３ＭｎＯ３中Ｚｎ的替代使电阻峰和磁阻峰的位置向低温区域大大移动，磁阻峰展宽．作者认为上述结果是由于Ｚｎ部分替代引起Ｍｎ离子的价态和磁矩的变化所造成的．更多还原

【Abstract】 The Zn substituted system, La 2/3 Ca 1/3 (Mn 1- x Zn x )O 3( x =0,0.15), was synthesized by solid state reaction method. Its temperature dependences of electrical resistance and magnetoresistance ( H =1 Tesla) and field dependence of magnetoresistance ( T =113K) were measured by four probe method. It was found that Zn substitution dramatically decreases the cusp temperatures in the ρ T curves under magnetic field as well as zero field. However the cusp is broadened by Zn substitution. The authors suggested that the change of cusp temperatures is relative to the change of manganese valence and the magnetic moments in the La 2/3 Ca 1/3 (Mn 1- x Zn x )O 3 system which is caused by Zn substitution.更多还原