Ching-Lin Chang1 and Haw-Yee Tsay1

1Department of Physics Tamkang University, Tamsui, Taiwan 25137, R.O.C.


 

Received: December 1, 1997
Accepted: June 18, 1998
Publication Date: June 18, 1998

Download Citation: ||https://doi.org/10.6180/jase.1998.1.1.03  


ABSTRACT


It is well known that the hole concentration is a crucial parameter for superconductivity of the high temperature superconductors. When Ca+2 replaces part of R+3 in fully oxygenated RBa2Cu3O7-δ. The hole concentration increases with Ca+2 concentration bring the system into the overdoping regime and causing the superconducting transition temperature Tc to drop. The sites of the extra hole and that of the Ca are the key factors to the understanding of the electrical transport property of this Ca doped system. We have performed the EXAFS on R1-xCaxBa2Cu3O7-δ ( R=Gd, Ho ) at room temperature to study effect of Ca doping on the local structure.


Keywords: EXAFS, R1-xCaxBa2Cu3O7-δ , High Temperature Superconductors.


REFERENCES


  1. [1]. Awana, V. P. S. and Narlikar, A. V., “Role of calcium in suppressing the superconductivity of Y1-xCaxBa2Cu3O7-δ,” Phys. Rev. B 49, 6353 (1994).
  2. [2]. Awana, V. P. S., Tulapurkar, A., Malik, S. K. and Narlikar, A. V., “Role of calcium in enhancing the super-conductivity of YBa2Cu3O7-y,” Phys. Rev. B 50, 594 (1994).
  3. [3]. Berastegui, P., Kakihana, M., Eriksson, S. G., Nishio, S., Mazaki, H., Yasuoka, H., Osada, M., Yashima, M. and Yoshimura, M., “Structure changes and redistribution of holes in Ca-doped YBa2Cu4O8,” Physica C 235-240, 377 (1994).
  4. [4]. Boyce, J. B., Bridges, F., Claeson T., Howland, R. S. and Geballe, “X-ray-absorption studies of YBa2Cu3O7- δ and GdBa2Cu3O7-δ superconductors,” T. H., Phys. Rev. B 36, 5251 (1987).
  5. [5]. Boyce, J. B., Bridges, F., Claeson, T. and Nygren, M., “Temperature dependence of the lacal structure of YBa2Cu3O7- δ with varying oxygen content: An x-ray-absorption study,” Phys. Rev. B 39, 6555 (1989).
  6. [6]. Claus, H., Yang, S., Paulikas, A. P., Downey, J. W. and Veal, B. W., “Atomic short-range order in deficient Y1-xCaxBa2Cu3O7-δ,” Physica C 171, 205 (1990).
  7. [7]. Fischer, P., Kaldis, E., Karpinski, J., Rusiecki, S., Jilek, E., Trounov, V. and Hewat, A. W., “Neutron diffraction analysis of 44Ca and Ca substituted super-conductors YBa2Cu4O8 with Tc~90 K,” Physica C 205,259 (1993).
  8. [8]. Guan, W., Chen, J. C. and Cheng, S. H., “Ion-size effect on transport properties in R0.9Ca0.1Ba2Cu3O7-δ systems (R=Tm, Ho, Gd, and Nd),” Phys. Rev. B 54, 3580 (1996).
  9. [9]. Jirak, Z., Hejtmanek, J., Pollert, E., Triska, A. and Vasek, P., “Structure and Superconductivity in Y1-xCax Ba2Cu3O7,” Physica C 156, 750 (1988).
  10. [10]. Lundqvist, P., Tegroth, C., Rapp, O., Tellgren, R. and Hegedus, Z., “Neutron-diffraction studies and inter-atomic distances in Ca-Pr doped NdBa2Cu3O7-δ,” Physica C 269, 231 (1996).
  11. [11]. Miceli, P. F., Tarascon, J. M., Greene, L. H., Phyne, J. J. and Neumann, D. A., “Magnetic ordering in YBa2Cu3-xMxO6+y,” Physica C 162-64, 1267 (1989).
  12. [12]. Neumeier, J. J., Bjornholm, T., Maple, M. B. and Schuller, I. K., “Hole filling and Pair Breaking by Pr Ion in YBa2Cu3O6.95±0.02,” Phys. Rev. Lett. 63, 2516 (1989).
  13. [13]. Watanabe, T., Fujiwara, M. and Suzuki, N., “super-conducting and electrical properrties of Ca-substituted YBa2Cu4O6,” Physica C 252, 100 (1995).
  14. [14]. Widder, K., Berner, D., Munzel, J., Geserich, H. P., Klaser, M., Muller-vogt, G. and Wolf, Th., “Charge carrier distribution in Y1-zCazBa2Cu3Ox,” Physica C 267, 254 (1996).
  15. [15]. Xiao, G. and Rebello, N. S., “Electrical transport and superconductivity in the (Y0.8Ca0.2)Ba2Cu3Oy system with variable oxygen content,” Physica C 211, 433 (1993); Fisher, B., Genossar, J., Kuper, G. C., Patlagan, L., Reisner, G. M. and Knizhnik, A., “Effect of substituting calcium for yttrium of the properties of YBa2Cu3O7-δ,” Phys. Rev. B 47, 6054 (1993).
  16. [16]. Yakabe, H., Kosuge, M., Tsujino, J., Shiohara, Y. and Koshizuka, N., “Correlation between Hall Numbers and Tc in Y1-xCaxBa2Cu3O7-δ (0≦x≦0.5) Thin Films Prepared by RF Thermal Plasma Deposition Method,” Jpn. J. Appl. Phys. 34, 4754 (1995).
  17. [17]. Zhang, K., Bunker, G. B., Zhang, G., Zhao, Z. X., Chen, L. Q. and Huang, Y. Z., “Extended x-ray-absorption fine-structure experiment on the hige-Tc superconductor YBa2Cu3O7-δ,” Phys. Rev. B 37, 3375 (1988). 


Latest Articles

    
 

0.6
2019CiteScore
 
 
27th percentile
Powered by  Scopus

SCImago Journal & Country Rank

Enter your name and email below to receive latest published articles in Journal of Applied Science and Engineering.