Correlation of Magnetic and Superconducting Properties with the Strength of the Magnetic Proximity Effect in La_0.67Sr_0.33MnO₃/SrTiO₃/YBa₂Cu₃O_7−δ Heterostructures

The effect of the stacking sequence on magnetic and superconducting properties in La0.67Sr0.33MnO3 (LSMO)/YBa2Cu3O7−δ (YBCO) and LSMO/SrTiO3/YBCO heterostructures, which consequently affected the magnetic proximity effect (MPE), was investigated using spin-polarized neutron reflectivity experiments. The results established the intrinsic nature of MPE and its correlation with stacking sequence-dependent magnetic and superconducting properties in these oxide heterostructure systems. We found an increase in the superconducting transition temperature (Tsc) and magnetization for both of the heterostructures as compared to heterostructures with a reversed stacking order. The evolution of the magnetization of the interfacial ferromagnetic (FM) layer, studied as a function of temperature for both heterostructures, showed a decrease in the MPE-induced magnetic depleted layer thickness for heterostructures at a higher Tsc. A comparison of the results of different studies with the present results suggested that the average magnetization and transition temperatures of a FM and a superconductor (SC) were important parameters that dictate the strength of the proximity effect due to the complex interaction of SC and FM in these systems. Tuning the strength of MPE in FM/SC and FM/I/SC oxide heterostructures may provide a promising platform for the effective realization of devices.