Superconducting properties of Be doped CUo.5 Tlo.5 Ba2(Ca1y Bey)( Zn I.5 Cuo.5)O8.0 superconductors

Abstract

We have e nhanced the sllperconducting prope rti es of newly discovered CUo.sT1o.sBa2Cu, (C ll O.sZ u)Oa.~ supercond uctor by doping Be at Cil sites. The slIpcrconducting properties, such as cri tical current density. infield magneti c properti es and quantity of dimnngnclislll. arc enhanced by De doping at the en sites. The decreased cMaxis length and the volume of the IInil cell have shown lhal inlcr·ZnOl- pl anc coupling is enhanced. We have 1101 observed any locali zi.lI ion of the carri ers ill the neighbourhood of Zn atoms in CUo.s TJo.sBa2Cal oyBcy (CuO.sZn I s)Otl-li (y=O, 0. 15, 0.30, 0.45, 0.6) superconductors, as proposed in the previolls studi es one must ex pect such e ffects ifprescnt, throl1 gh the decreased c-ax is length by l3e doping. The decreased c~ s length ~s ld[s in enhancement of coherence length and rll1i ~ve oc ity of the carriers, which in tllrn result in enhanced superconducti vity parameters. The presence of Be at the termination ends o f tilt;! crystals results in enhanced inter-grain coupling and substantia lly improved the ir weak link behaviour. The opt imi za ti on of the ca rriers in Cu0 2/Zn02-plllIlCS hnve been found to enhance the Tc(R=O) and thl! magnitude of diamagnetism ill e~ doped sampl es. Also the sofie ning o f phonon modes with the increased l3e doping evidenced the incorpo ra tion ofZI1 at the CU02 planar sites