Superconductivity Suppression In Yba2cu3o7-Delta/La0.7sr0.3mno3 Bilayer Films

We study the thickness effect of YBa2Cu3O7-delta (YBCO) in YBCO/La0.7Sr0.3MnO3 (LSMO) bilayer films, fabricated on LaAlO3 (001) substrate using pulsed laser deposition technique. The thickness dependent transport behavior of YBCO layer in considered bilayer systems demonstrate a clear onset critical temperature at 60K and 80K for 100 nm and 200 nm thick YBCO layer systems, respectively, whereas 50 nm thick YBCO system reveals complete suppression in the superconductivity. With the increase in thickness of YBCO layer, the magnetoresistance (MR) data show both positive and negative MR. The positive MR in superconducting regime dominates the negative MR, suppress the double exchange interaction. The maximum magnetoresistance ratio similar to 81% at 64K and similar to 47% at 30K temperature are observed for 200 nm and 100 nm YBCO layers, respectively. In YBCO(200 nm)/LSMO(200 nm) bilayer specimen, the temperature co-efficient of resistance is similar to 8.4% K-1 at 72K which can be practical for bolometric performances and temperature sensors. (C) 2014 AIP Publishing LLC.