Response of Cu_0.5(Tl_0.5−yHg_y)Ba₂Ca₃Zn₂Cu₂O₁₂₋ (y=0, 0.15, 0.25 and 0.35) superconductors in electric and magnetic fields

The superconducting properties of the Cu_0.5(Tl_0.5−yHg_y)Ba₂Ca₃Zn₂Cu₂O₁₂₋ compound have been studied by resistivity and ac magnetic susceptibility measurements. Mercury substitution has been found to improve the superconductivity of the Cu_0.5Tl_0.5Ba₂Ca₃Zn₂Cu₂O₁₂₋ (CuTl-1234) compound, which is evidenced by the improvement of physical properties such as zero resistivity critical temperature, critical current density and flux pinning. The main objective of the present study was to examine the possible role of Hg in enhancing the superconducting properties of CuTl-1234. Post-annealing of the samples was also carried out at 550 °C in an oxygen atmosphere. The oxygen post-annealing enhanced the intergranular coupling and the superconducting properties of Cu_1−xTl_x-1234 samples. But ac susceptibility measurements under different magnetic fields show that CuTlHg-1234 has superior flux pinning characteristics as compared to Cu_1−xTl_x-1234, which make them useful for applications in external magnetic fields. ©2010

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