The effects of strain, current, and magnetic field on superconductivity in Pr0.5Ca0.5MnO3/YBa2Cu3O7/Pr0.5Ca0.5MnO3 trilayer

Abstract

Thin film trilayers of Pr0.5Ca0.5MnO3/YBa2Cu3O7/Pr0.5Ca0.5MnO3 have been deposited on MgO substrate by pulsed laser deposition technique. The film thicknesses were selected so that in one of the trilayers, the bottom Pr0.5Ca0.5MnO3 layer is thin, and hence, subjected to substrate induced strain, while in another trilayer, the bottom layer is sufficiently thick to ensure that it is not subjected to such strain. Current and magnetic field dependent resistance measurements have been carried out on the trilayers down to liquid helium temperatures to investigate the influence of charge-order melting and the consequent formation of ferromagnetic clusters in the Pr0.5Ca0.5MnO3 film on the superconducting properties of YBa2Cu3O7. These measurements show that the suppression of the superconducting transition temperature (Tc) of YBa2Cu3O7 is relatively high for the strained trilayer compared to that observed for the other. The activation energy for hopping of vortices in the sandwiched YBa2Cu3O7 film was estimated from an analysis of the data; the vortex pinning force was found to be higher for the strained trilayer. The experimental results suggest the possibility of simultaneous use of strain, current, and magnetic field to control the superconducting behavior of the sandwiched YBa2Cu3O7 layer.