Analysis of the magneto-transport properties of superconducting/ferromagnetic YBa2Cu3O7/La0.7Sr0.3MnO3 bilayer thin films

Strain-induced local structural change and its effect on the superconducting properties of GdBa2Cu3O7-x /La0.7Sr0.3MnO3 heterostructure

“…An intriguing part of the T c behavior in our system is; unlike very thin-SC/FM heterostructures which showed a semiconducting behavior in the normal state and a special characteristic of dual transition [12,17,18,22], our relatively thick-GdBCO/LSMO samples do not exhibit a significant effect of interaction between SC and FM. In this case, the superconducting mechanism in the thick-SC/FM structure may dominantly depend on the characteristics of local structure, i.e.…”

“…Pena et al pointed out that each effect governs depending on its characteristic length scale such as the superconducting coherence length or the spin diffusion length, and the length scale in which the superconductivity of REBCO is depressed by spin polarized carriers is ~10 nm [21]. This implies a possible inhomogeneous distribution of both the weak superconducting layer placed adjacent to the FM layer and the strong superconducting layer in the rest of the film [21,22]. If the thickness of the SC layer is thick enough to consider that the superconducting properties are less dependent on the ferromagnetic effect, the strain state of the heterostructure is expected to have a profound impact on T c .…”

Proximity effect in La0.7Sr0.3MnO3/Bi2Sr2CaCu2O8hybrid bi-layers

“…The temperature-dependent electrical resistivity ρ(T) of a bi-layer sample is an indirect measure of sample quality [42] and its behavior near T con is very sensitive to asperities at the interface. Suppression of the metallic behavior and the appearance of semiconducting behavior has been observed in LSMO/YBCO bi-layers [33] and in LCMO-Bi-2212, LCMO-YBCO bi-layers [43,44] due to inter-diffusion. However, if the interface asperities are significant, the value of ρ near T con should have increased greatly along with a random fluctuation in T C due to varying superconducting percolation paths, which we do not observe here (figure 3).…”

“…The M-H loop of the B5 single layer measured at 5 K (figure 8(a)) displays the superconducting diamagnetic property of Bi-2212 with a characteristic star-like curve with a finite pinning force. Whereas, the L4/B5 bi-layer, having the thinnest (40 nm) LSMO underlayer, shows a deformed superconducting loop with a observable ferromagneticlike feature (figure 8(b)), which results from the partial suppression of the superconducting order parameter due to the presence of the ferromagnetic LSMO underlayer [33,34].…”