掺Pr的Y-Ba-Cu-O体系超导体的红外光谱研究  

INFRARED SPECTRA OF Pr-DOPED Y-Ba-Cu-O SYSTEM SUPERCONDUCTORS

作　　者：曾文生[1] 杨小明[2] 李增发[3] 张光寅[3] 宋德英[2] 阎少林[4] 

机构地区：[1]中山大学物理系,广州510275 [2]南开大学化学系,天津300071 [3]南开大学物理系,天津300071 [4]南开大学电子科学系,天津300071

出　　处：《物理学报》1992年第10期1567-1574,共8页Acta Physica Sinica

摘　　要：本文报道了对Pr_xY_(1-x)Ba_2Cu_3O_(7-δ)体系超导体红外光谱研究的结果。发现在整个光谱范围内(中红外和远红外),Pr含量增加的直接结果是大部分反射峰的强度增强。在远红外区,Y原子的“指纹”性声子190cm^(-1)峰的频率位置与Pr含量无关,证明了Pr在该体系中价态要比Y的+3价高,介于+3价与+4价之间。通过对各个声子结构的指认,我们发现:随Pr含量增高,声子活性增强的振动模必定是属于CuO_2面内的或与CuO_2平面平行的振动模,与YBa_2Cu_3O_(7-δ)体系中减少氧的情况类似。这意味着CuO_2面内的振动对于高温超导性的重要作用。The result of studies on the infrared spectra of PrxYl-xBa2Cu3O7-δ system superconductors are reported. It is found that the direct result of increasing the Pr content is that most reflectance features become stronger in the whole energy range (including midle infrared and far infrared). The fingureprint phonon of Y atom at 190cm-1 does not shift when the content of Pr changes. This confirm, that the valence of Pr in this system is greater than +3, which is the valence value of Y in YBa2Cu3O7-δ, and should be between +3 and +4. We also found that, after making the assignment of all phonons, the vibration modes whose strengths increase when the content of Pr increases must be the vibration modes in the CuO2 plane or parallel to the CuO2 plane. This case is much similar to the situ ation of decreasing oxygen content in the YBa2Cu3O7-δ system. It is showed that these vibrations in the CuO2 plane are important for the high-Tc superconduccivity.

关 键 词：YBCO 超导体 镨 高温超导性 

分 类 号：O511.1[理学—低温物理]