Abstract
We report the results of transport measurements on single-crystal YBa2(Cu1-xZnx)3O7-δ thin films grown by laser ablation. Matthiessen’s rule is obeyed as a function of x at optimum doping (δ∼0.05), but is violated in underdoped samples, where there is evidence from the resistivity that zinc fills in the pseudogap that is observed for samples with x=0, δ ≳0.2. As x and δ are increased, Tc drops rapidly, and a superconductor-insulator transition is observed at a sheet resistance of approximately h/(2e)2 per copper-oxygen bilayer, for various different combinations of x and δ.
