MAGNETIC PENETRATION DEPTH AND CONDENSATE DENSITY OF CUPRATE HIGH-T-CSUPERCONDUCTORS DETERMINED BY MUON-SPIN-ROTATION EXPERIMENTS

We summarize our results of transverse-field muon-spin-relaxation (TF- mu SR) experiments on a variety of polycrystalline cuprate high-T-c su perconducting systems. In this paper we present the conditions under w hich the mu SR depolarization rate at low temperatures sigma(0) propor tional to lambda(ab)(-2)(0) proportional to n(s)(0)/m(ab) is determin ed in a unique way by the doping state of CuO2 planes and the conseque nt critical temperature T-c. Disorder and pinning effects due to vario us sorts and amounts of dopant atoms do not affect sigma(0). From our results on YBa2CU3O77-delta, YBa2Cu4O8, and Y2Ba4CU7O15-delta (systems having both planes and chains) we conclude that a superconducting con densate is not only formed in the CuO2 planes but is induced additiona lly in the CuO chains. This chain condensate is rapidly suppressed by any disorder in the chains and depends strongly on the oxygen ordering .