The microwave surface impedance of YBa2Cu3O7-delta

A complete set of measurements of the anisotropic penetration depth (lambda(a), lambda(b), lambda(c)) of YBa(2)Cu(3)O(7-delta)indicates that the qualitative behaviour of the superfluid density is the same in both the T-c = 60 K and 93 K phases of this material. The linear behaviour of lambda(a) and lambda(b) and the relatively flat temperature dependence of lambda(c) at low temperatures seem to depend little on the oxygen doping of the CuO chains. The penetration depth is also largely unaffected by impurities except for the case of Zn doping which quickly gives rise to gapless behaviour. The surface resistance is strongly affected by both Ni and Zn doping but only Zn changes the linear temperature dependence of R(3) at low temperatures.