Magnetic penetration depth in epitaxial Nd-doped R(NdxBa2-x)Cu3O7 (R = Y and Nd) films

The temperature dependence of the in plane magnetic penetration depth lambda(ab)(T) of high quality c-axis epitaxial Nd-rich R(NdxBa2-x)Cu3O7 (R = Y, Nd) films has been measured at 4 MHz, 1.4 and 19.8 GHz with different techniques. While for stoichiometric films lambda(ab)(T) proportional to T, the Nd-rich films exhibit a quadratic temperature dependence of lambda(ab)(T) with a slope partial derivativelambda(ab)(T)/partial derivativeT(2) that decreases with the increasing frequency. The experimental results are discussed in the framework of the d-wave, dirty model. (C) 2003 Elsevier B.V. All rights reserved.