Suppressed ${{B}}_{c2}$ in a superconducting/ferromagnetic bilayer

Abstract

We investigate the influence of a ferromagnetic layer (La 0.7 Sr 0.3 MnO 3 ) on the upper critical field of YBa 2 Cu 3 O 7−δ superconducting layer in a superconductor/ferromagnet (SC/FM) hybrid structure. The YBa 2 Cu 3 O 7−δ /La 0.7 Sr 0.3 MnO 3 (YBCO/LSMO) hybrid bilayers as well YBCO single layer were fabricated on (001) LaAlO 3 (LAO) substrate using pulsed laser deposition.The temperature dependent upper critical field ( ) B T c2of type-II superconductors are generally described in the frameworks laid down by Werthamer-Helfand-Hohenberg and Ginzburg-Landau. We employ both formalism to estimate ( ) B T c2 of YBCO from magneto-transport data in SC/FM bilayers of varying ferromagnetic layer thickness as well as for YBCO single layer. We find that the ( ) B T c2 of YBCO in YBCO/LSMO bilayer gets suppressed as compared to that of single YBCO layer. Further to this, we also observe that the ( ) B T c2 of YBCO in the bilayer system decreases with increasing ferromagnetic LSMO layer thickness. These two results are discussed in the light of magnetic proximity effect, spin-diffusion induced pair breaking and enhanced effective magnetic field experienced by the YBCO layer with increasing ferromagnetic LSMO layer thickness.

The effect of Sn intercalation on the superconducting properties of 2H NbSe2

“…To compare how B C2 -T c phase evolves with Sn-intercalation, we employed ρ-T plots under applied magnetic field to extract the same. The temperature dependent upper critical field for type-II superconductors is well described by Werthamer-Helfand-Hohenberg (WHH) formalism [30][31][32].…”