Absence of a pair-breaking mechanism in Cu(0.5)Tl(0.5)Ba(2)Ca(3)Cu(4-y)Zn(y)O(12-delta)

作者：Khan Nawazish Ali^*; Mumtaz Muhammad

来源：Physical Review B, 2008, 77(5): 054507.

DOI：10.1103/PhysRevB.77.054507

A high temperature Cu(0.5)Tl(0.5)Ba(2)Ca(3)Cu(4-y)Zn(y)O(12-delta) (y=0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5) superconductor with four ZnO(2) planes is synthesized, in which the zero resistivity critical temperature [T(c)(R=0)], the quantity of diamagnetism, and critical current density (J(c)) are found to increase with enhanced Zn doping. From the x-ray diffraction studies, the c-axis lengths are found to decrease with increased Zn doping in Cu(0.5)Tl(0.5)Ba(2)Ca(3)(Cu(4-y)Zn(y))O(12-delta). The softening of apical oxygen modes observed in Fourier transform infrared absorption measurements has shown that the decreased c-axis length is among CuO(2)/ZnO(2) planes. The decreased c-axis length increases the Fermi vector k(F), the coherence length xi(c), and the superconductivity order parameter, which result into enhanced superconducting properties. The superconducting properties in these compounds were further enhanced by optimizing the carriers in CuO(2)/ZnO(2) planes. The optimum numbers of carriers in these compounds were achieved by postannealing the samples in oxygen atmosphere.

• 出版日期2008-2