样品制备过程中不同冷却速率对Nd_(1.85)Ce_(0.15)CuO_(4±δ)单晶正常态和超导态输运性质的影响  

THE INFLUENCE OF COOLING RATES IN SAMPLES PREPARATION ON NORMAL AND SUPERCONDUCTING STATE TRANSPORT PROPERTIES OF Nd_(1.85)Ce_(0.15)CuO_(4±δ) ELECTRON-DOPED SINGLE CRYSTAL

作　　者：陈旭东[1] 杨宏顺[2] 柴一晟[2] 刘剑[2] 钟声[2] 孙成海[2] 高慧贤[2] 薛璟[2] 段理[2] 曹烈兆[1] 

机构地区：[1]中国科学技术大学结构分析开放实验室 [2]中国科学技术大学物理系,合肥230026

出　　处：《低温物理学报》2006年第4期325-329,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金(批准号:10374082)资助的课题.~~

摘　　要：通过原子力显微镜(AFM)对Nd_(1.85)Ce_(0.15)CuO_(4±δ)(NCCO)单晶样品的微结构进行分析,发现样品在制备和热处理过程中存在分解反应Nd2-xCexCuO4→(Nd,Ce)2O3+NdCeO3.5+Cu2O发生的证据,控制样品冷却速率可得到(Nd,Ce)2O3分解物含量不同的单晶样品.ab面电阻率测量结果表明,降低冷却速率可有效减少分解过程的发生、减少有效载流子浓度的降低和减少对Cu2O上Cu2+-Cu2+反铁磁关联的破坏,有利于保持体系结构上的均匀性和稳定性,是制备高品质电子型超导体Nd2-xCexCuO4单晶的关键.The results of atomic force microscopy （AFM） revealed the existence of the partial decomposition of Nd1.85Ce0.15CuO4＋δ（NCCO） single crystal in the processes of samples preparation and heat treatment. By changing cooling rates in the processes, the content of one of the decomposition products, （Nd, Ce）2O3 will be changed in the crystals. The in-plane resistivities of single crystals Nd1.85 Ce0.15 CuO4＋δ with different cooling rate were measured, indicating that the decreasing of the cooling rate could effectively reduce samples decomposition, thus, prevent charge carrier concentration from decreasing and the antiferromagnetic order on Cu-O sheets from destructing. Moreover, it could keep the crystal stoichiometric homogeneous and structure steady.

关 键 词：电子型超导体 样品制备 电阻率 

分 类 号：O511.2[理学—低温物理]