10 GHz surface impedance measurements of (Y,Er)BaCuO films produced by MOCVD, laser ablation, and sputtering

A parallel-plate resonator technique previously used to measure microwave surface resistance R/sub s/(T) has been extended to measure absolute penetration depth lambda (T). Measurements of both quantities near 10 GHz from 4.2 K to T/sub c/ are reported for ErBaCuO thin films produced by metalorganic chemical vapor deposition (MOCVD) and for YBaCuO thin films produced by laser ablation and single-target off-axis sputtering. Each production method gives rise to films whose surface resistance is below 1 m Omega at temperatures below 40 K. The low-temperature penetration depths range from 250 nm for the laser ablation and sputtered films to 800 nm for the MOCVD films. The penetration depths in all cases increase with temperature according to the Gorter-Casimir temperature dependence.