太赫兹瞬态光谱研究La_(0.7)Ca_(0.3)MnO_(3)薄膜的温度相关相变  

The temperature-dependent phase transition in La_(0.7)Ca_(0.3)MnO_(3) film probed with terahertz transient spectroscopy

作　　者：李高芳 许艳霞[1] 刘现款 马国宏 高艳卿[3] 崔昊杨[1] 黄志明 褚君浩[3] LI Gao-Fang;XU Yan-Xia;LIU Xian-Kuan;MA Guo-Hong;GAO Yan-Qing;CUI Hao-Yang;HUANG Zhi-Ming;CHU Jun-Hao(School of Electronic&Information Engineering,Shanghai University of Electric Power,Shanghai 200082,China;Department of Physics,Shanghai University,Shanghai 200444,China;State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China)

机构地区：[1]上海电力大学电子与信息工程学院,上海200082 [2]上海大学物理系,上海200444 [3]中国科学院上海技术物理研究所红外物理国家重点实验室,上海200083

出　　处：《红外与毫米波学报》2021年第4期490-495,共6页Journal of Infrared and Millimeter Waves

基　　金：Supported by National Natural Science Foundation of China(11674213,61735010,11647023,61625505);Natural Science Founda‐tion of Shanghai(17ZR1411500)。

摘　　要：利用太赫兹瞬态光谱研究了La_(0.7)Ca_(0.3)MnO_(3)薄膜的热力学性质。La_(0.7)Ca_(0.3)MnO_(3)薄膜的金属-绝缘体相变温度在260 K左右,与铁磁-顺磁相变温度几乎相同。结果表明,La_(0.7)Ca_(0.3)MnO_(3)薄膜的电导率与薄膜中磁矩取向密切相关。研究发现在40∼200 K的低温范围内,La_(0.7)Ca_(0.3)MnO_(3)薄膜的电导率可以用Drude模型拟合,在210∼290 K的高温范围内可以用Drude-Lorentz模型拟合。The thermodynamics of La_(0.7)Ca_(0.3)MnO_(3) film by terahertz transient spectroscopy were presented.The temperature of metal-insulator phase transition of La_(0.7)Ca_(0.3)MnO_(3) film is observed to occur around 260 K,which is almost the same as that of the ferromagnetic-paramagnetic phase transition.It indicates that the conductivity of the La_(0.7)Ca_(0.3)MnO_(3) film is closely related to the order of magnetic moments in the film.We find the conductivity of the La_(0.7)Ca_(0.3)MnO_(3) film can be reproduced with Drude model at low temperature range from 40 K to 200 K,and Drude-Lorentz model at high temperature region from 210 K to 290 K.

关 键 词：金属-绝缘体相变 铁磁-顺磁相变 太赫兹电导率 La_(0.7)Ca_(0.3)MnO_(3)薄膜 

分 类 号：O433.1[机械工程—光学工程]