摘要
对Ｓｍ ２／３Ｓｒ１／３ ＭｎＯ３＋ δ巨磁电阻材料样品在７７ Ｋ 至室温范围进行了正电子寿命谱和多普勒展宽谱测量．结果显示，正电子平均寿命τｍ 随着温度的降低在２００～１５０ Ｋ 温区出现与晶格结构不稳定有关的反常下降， 这一过程发生在磁有序起始温度之前；而伴随着绝缘体－金属型转变（１１５ Ｋ），多普勒展宽谱参数Ｓ明显增加，表明了电子的离域化．
The measurements of positron lifetime spectra and Doppler broadening radiation spectra ranging from 77K to room temperature on the sample of Sm 2/3 Sr 1/3 MnO 3+ δ Compound have been carried out. An anomalous dip of mean lifetime τ m within the temperature range from 200K to 150K has been observed, which is in relation to the instability of lattice structure, and is occurred before the magnetic ordered initial temperature. Meanwhile, accompanying the isulator metal transition, the line shape parameters S of Doppler broadening spectra increase remarkably, which indicates the localization of the electrons. The results are discussed.
出处
《华中理工大学学报》
CSCD
北大核心
1999年第12期19-20,23,共3页
Journal of Huazhong University of Science and Technology
基金
中国科学院核分析技术开放研究实验室资助
关键词
晶格不稳定性
巨磁电阻材料
锰氧化物
钙钛矿型
Sm_(2/3)Sr_(1/3)MnO_(3+δ)
positron annihilation technique
lattice instability
