ure 6. As it can be seen from this figure, the resistivity of YBa2(Cu1−xCox)3O7−δ samples vs. temperature shows that for the onset transition temperature is Tconset ~ 88˚K, 82˚K, 81˚K and 80˚K for x = 0, 0.002, 0.004 and 0.006 Co respectively. Decrease in the number of hole carriers by impurity doping to the CuO chain should be responsible for reduced Tc of YBCO phase Cobalt doping, this reduction has been estimated to 2 - 8 K/at% for trivalent dopants (M: Fe, Co and Al) [23] . All samples show metallic behavior in the normal state, with high resistivity comparing to undoped sample. The residual resistivity (ρ0) is found by linear extrapolation of the resistivity curve in the range from 2Tc up to room temperature.

Figure 6. Variation of the resistivity as function of Co content in YBa2(Cu1−xCox)3O7−δ.

Figure 7. The onset of superconducting transition temperature Tco and residual resistivity variation ρ0 as function of Co content in YBa2(Cu1−xCox)3O7−δ.

As an inherent property of conducting materials, ρ0 is modified progressively with the added composites (Figure 7). This signifies that inter granular connectivity is also modified by these composites. The residual resistivity is considered as an indicator of the sample homogeneity and defects density. The higher residual resistivity value corresponding to the sample doped with x = 0.06, these results are confirmed by the porous structure obtained in the micrographs analysis. Co doping makes the temperature dependence of the resistivity ρ (T) deviate from linear behavior at T, especially for the sample doped with x = 0.04 and x = 0.06. This deviation is related to the opening of a pseudogap. As discussed for oxygen depleting crystals [24] .

4. Conclusion

The effect of Cobalt doping on the microstructure and the normal state transport properties of polycrystalline YBCO was studied. Samples have been elaborated by the solid state reaction method and characterized by means of XRD, SEM, DTA and resistivity measurements. The crystal lattice parameters are found to change due to the cobalt doping and tendency to a structure phase transition from orthorhombic to tetragonal, which is confirmed by the decrease of the degree of orthorhombicity (b − a)/(b + a). The variation of full width half maximum (FWHM) of (00l) peaks as function of Co content reveals that there is a microstructural disorder caused by the cobalt incorporation. The thermal analysis of our samples reveals that the YBCO decomposition temperature is greatly lowered. In addition, the morphology examination with SEM revealed gradual increases of grain size with x = 0.02 Co; a high porosity is observed in the doped samples compared to the undoped. The resistivity measurements show a deviation from linearity of ρ(T), it is due to the opening of a pseudogap in Co doped samples.

Cite this paper

Chamekh, S. and Bouabellou, A. (2018) The Effects of Magnetic Dopant on the Structural and Electrical Properties in Superconducting YBaCu3O7−δ Ceramic. Advances in Chemical Engineering and Science, 8, 1-10. https://doi.org/10.4236/aces.2018.81001

References

  1. 1. Yilmaz, M. and Dogan, O. (2011) Structural and Electrical Properties of Niobium Doped Y0.6Gd0.4Ba2-xNbxCu3O7-y Superconductors. Materials Sciences and Application, 2, 1090-1096. https://www.scirp.org/Journal/PaperInformation.aspx?PaperID=6720 https://doi.org/10.4236/msa.2011.28147

  2. 2. Maeno, Y., Kato, M., Aoki, Y., Nojima, T. and Fujita. T. (1987) Superconductivity in Modified Systems Based on YBa2Cu3O7-δ. Physica B+C, 148, 357-359. http://www.sciencedirect.com/science/article/pii/0378436387902336 https://doi.org/10.1016/0378-4363(87)90233-6

  3. 3. Ben Azzouz, F., Zouaoui, M., Mani, K.D., Annabi, M., Tendeloo, G.V. and Ben Salem, M. (2006) Structure, Microstructure and Transport Properties of B-Doped YBCO System. Physica C, 442, 13-19. http://www.sciencedirect.com/science/article/pii/S0921453406002656 https://doi.org/10.1016/j.physc.2006.03.135

  4. 4. Zhang, L., Sun, X.F., Chen, X. and Zhang, H. (2003) Different Effects of Zn and Pr Doping on YBa2Cu3O7-δ-δ. Physica C, 386, 271-274. http://www.sciencedirect.com/science/article/pii/S0921453402021251 https://doi.org/10.1016/S0921-4534(02)02125-1

  5. 5. Liu, Y.H., Che, G.C., Li, K.Q., Zhao, Z.X., Kou, Z.Q., Di, N.L. and Cheng, Z.H. (2005) The Influence of Local Structure on Superconductivity in Fe0.5Cu0.5Ba2YCu2O7.41: A Mossbauer Effect Study. Physica C, 418, 63-67. http://www.sciencedirect.com/science/article/pii/S0921453404013413 https://doi.org/10.1016/j.physc.2004.11.002

  6. 6. Giri, R., Awana, V.P.S., Singh, H.K., Tiwari, R.S., Srivastava, O.N., Gupta, A., Kumaraswamy, B.V. and Kishan, H. (2005) Effect of Ca Doping for Y on Structural/Micristructural and Superconducting Properties of YB2Cu3O7-δ. Physica C, 419, 101-108. http://www.sciencedirect.com/science/article/pii/S0921453405000146 https://doi.org/10.1016/j.physc.2005.01.002

  7. 7. Wang, P., Li, J., Peng, W., Chu, H.F., Li, S. and Zheng, D.N. (2007) Growth of YBa2Cu3O7-δ and La0.67Ca0.33MnO3 Thin Films on Silicon-on-Insulator Substrates. Physica C, 460-462, 1367-1368. http://www.sciencedirect.com/science/article/pii/S0921453407005023 https://doi.org/10.1016/j.physc.2007.04.128

  8. 8. Singhal, R.K. (2010) How the Substitution of Zn for Cu Destroys Superconductivity in YBCO System? Journal of Alloys and Compounds, 495, 1-6. http://www.sciencedirect.com/science/article/pii/S0925838810001398 https://doi.org/10.1016/j.jallcom.2010.01.106

  9. 9. Murugesan, M., Obara, H., Sawa, A., Kosaka, S., Nakagawa, Y., Nie, J.C. and Yamasaki, H. (2003) Microwave Surface Resistance of under Doped Co Substituted YBCO Films. Physica C, 400, 65-70. http://www.sciencedirect.com/science/article/pii/S0921453403013297 https://doi.org/10.1016/S0921-4534(03)01329-7

  10. 10. Liu, L., Dong, C., Zhang, J. and Li, J. (2002) The Microstructure Study of Co-Doped YBCO System. Physica C, 377, 348-356. http://www.sciencedirect.com/science/article/pii/S0921453401012862 https://doi.org/10.1016/S0921-4534(01)01286-2

  11. 11. Sydow, J.P. and Buhrman, R.A. (1999) Effect of Ozone Anneals on YBa2Cu3-xCoxOz in Films. IEEE Transactions on Aplied Superconductivity, 9, 1994-1997. http://ieeexplore.ieee.org/document/784854/?section=abstract

  12. 12. Pignon, B., Autret-Lambert, C., Ruyter, A., Decourt, R., Bassat, J.M., Monot-Laffez, I. and Ammor, L. (2008) Study of the Yttrium and Zinc Substitutions Effects in Bi2Sr2CaCu2O8+δ Compounds by Transport Measurements. Physica C, 468, 865. http://www.sciencedirect.com/science/article/pii/S0921453407013056 https://doi.org/10.1016/j.physc.2007.09.014

  13. 13. Xiao, G., Bakhshai, A., Cieplak, M.Z., Tesanovic, Z. and Chien, C.L. (1989) Correlation between Superconductivity and Normal-State Properties in the La1.85Sr0.15(Cu1-xZnx)O4 System. Physical Review B, 39, 315-321. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.39.315 https://doi.org/10.1103/PhysRevB.39.315

  14. 14. Raffo, L., Caciuffo, R., Rinaldi, D. and Licci, F. (1995) Effects of Mg Doping on the Superconducting Properties of YBa2Cu3O7-delta and La1.85Sr0.15CuO4 Systems. Superconductor Science and Technology, 8, 409. http://iopscience.iop.org/article/10.1088/0953-2048/8/6/003/pdf https://doi.org/10.1088/0953-2048/8/6/003

  15. 15. Tonneau, J. (2000) Table de chimie, Edition de Boeck université., Belgique. https://www.decitre.fr/livres/tables-de-chimie-9782804133016.html

  16. 16. Attaf, S., Mosbah, M.F., Fittipaldi, R., Zola, D., Pace, S. and Vecchione, A. (2012) Effect of Double Substitution on Structural and Magnetic Properties of Y1-xCaxBa2(Cu1-yMgy)3O7-δ. Physica C, 477, 36-42. http://www.sciencedirect.com/science/article/pii/S0921453412000731 https://doi.org/10.1016/j.physc.2012.02.031

  17. 17. Xue, R., Dau, H., Chen, Z., Li, T. and Xue, Y. (2013) Effects of Zn Doping on Crystal Structure, Raman Spectra and Superconductivity of SmBa2Cu3O7-δ Systems. Materials Science and Engineering B, 178, 363-367. http://www.sciencedirect.com/science/article/pii/S0921510713000172 https://doi.org/10.1016/j.mseb.2013.01.004

  18. 18. Elizabeth, S., Anand, A., Bhat, S.V., Subramanyam, S.V. and Bhat, H.L. (1999) Influence of Cobalt Doping on Superconducting Transition in As-Grown YBCO Single Crystals. Solid State Communications, 109, 333-338. http://www.sciencedirect.com/science/article/pii/S0038109898005535 https://doi.org/10.1016/S0038-1098(98)00553-5

  19. 19. Chuang, F.Y., Sue, D.J. and Sun, C.Y. (1995) Effects of Silver Doping on the Superconducting YBa2Cu3O7-δ. Materials Research Bulletin, 30, 1309-1317. http://www.sciencedirect.com/science/article/pii/0025540895001107 https://doi.org/10.1016/0025-5408(95)00110-7

  20. 20. Chamekh, S., Bouabellou, A., Elerman, Y., Kaya, M. and Dincer, I. (2017) Effects of Nickel Substitution on Crystalline Structure and Superconducting Properties of YBa2Cu3O7-δ Ceramics. Journal of New Technology and Materials, 7, 22-29. https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxqbnRtam91cm5hbHxneDo1ZWE2Mzk0ODM2ZjIyOWVk

  21. 21. Tiagi, A.K., Tiagi, S. and Sharma, T.P. (1997) About the Substitution for CuO in YBCO High Temperature Superconductors. Materials Science and Engineering, 45, 88-97. http://www.sciencedirect.com/science/article/pii/S0921510796019125 https://doi.org/10.1016/S0921-5107(96)01912-5

  22. 22. Suxiang, H. and Yanli, Z. (2004) The Anomalies of Transport Properties Due to the Normal-State Pseudogap in Co and Zn Doped YBa2Cu3O6+δ This Films. Superconductor Science and Technology, 17, 833-837. http://iopscience.iop.org/article/10.1088/0953-2048/17/7/003/meta https://doi.org/10.1088/0953-2048/17/7/003

  23. 23. Mahtali, M., Chamekh, S., Boucherka, T. and Bouabellou, A. (2006) Effects of Zn Doping on YBaCuO Superconductor. Physica Status Solidi, 9, 3040-3043. http://onlinelibrary.wiley.com/doi/10.1002/pssc.200567137/abstract https://doi.org/10.1002/pssc.200567137

  24. 24. Yao, X., Oka, A., Izumi, T. and Shiohar, Y. (2004) Crystal Growth and Superconductivity of Fe-Doped YBCO Single Crystals. Physica C: Superconductivity, 339, 99-105. http://www.sciencedirect.com/science/article/pii/S0921453400003336

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