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(La1-xYx)2/3Ca1/3MnO3体系的正电子湮没研究
POSITRON LIFETIME STUDY ON THE AS-PREPARED Y-DOPED La2/3Ca1/3MnO3 OXIDES
【摘要】 为研究超大磁阻材料的掺杂效应 ,我们测量了 (La1 -xYx) 2 / 3 Ca1 / 3 MnO3 系列样品的正电子寿命谱 ,并结合X射线衍射和电阻温度关系的测量结果 ,系统地研究了Y掺杂引起的样品局域电子结构和空位型缺陷的变化 ,并提出了局域电荷转移的观点 ,解释正电子体寿命的变化 .
【Abstract】 The positron lifetime as a function of the Y content x was measured for the as prepared samples of (La\-\{1- x \}Y\- x )\-\{2/3\}Ca\-\{1/3\}MnO\-3. A long lived lifetime of about 450ps was observed. The long lived lifetime has an obvious increase for the low content x , then a slow increase when x is large enough. The monotonous increase of the bulk lifetime for the samples implied that there exists local charge transfer. The changes of the microstructure with Y content were discussed.
【基金】 国家自然科学基金! (批准号 198750 50 );中国科学院院长基金及教育部留学回国人员科研启动费的资助
- 【文献出处】 低温物理学报 ,CHINESE JOURNAL OF LOW TEMPERATURE PHYSICS , 编辑部邮箱 ,2000年03期
- 【分类号】TM27
- 【被引频次】2
- 【下载频次】39