Magneto-Transport and Flux Pinning in YBa2Cu3O7-δ/La0.7Sr0.3MnO3 Heterostructure Thin Films Grown on LaAlO3 via Pulsed Laser Deposition

We demonstrate the successful fabrication of high-quality, c-axis-oriented YBa 2 Cu 3 O 7-δ (YBCO) and YBCO/La 0.7 Sr 0.3 MnO 3 (LSMO) heterostructure thin films on LaAlO 3 (LAO) substrates using pulsed laser deposition. X-ray diffraction confirms excellent crystallinity, phase purity, and coherent epitaxial strain, with YBCO under slight tensile strain and LSMO experiencing stronger compressive strain arising from lattice mismatch. Magnetization measurements reveal that the superconducting transition temperature is reduced by ~4 K in the YBCO/LSMO/LAO stack compared to the YBCO/LAO film, and the M(T) behavior reflects the combined signatures of YBCO superconductivity and LSMO ferromagnetism. A notable diamagnetic response persists up to nearly 120 K, indicating superconducting fluctuations above T sc . The heterostructure also exhibits substantially enhanced magnetoresistance, highlighting strong interfacial coupling between the superconducting and ferromagnetic layers. The critical current density, evaluated using the extended Bean model, shows a characteristic triple-crossover with magnetic field, arising from modified vortex dynamics driven by interfacial magnetic inhomogeneity. Dew-Hughes analysis indicates dominant δT sc -type point pinning at low temperature, a δℓ-type surface pinning regime at intermediate temperature, and mixed pinning near T sc . In contrast, the single-layer YBCO/LAO film follows the conventional point–surface–volume pinning sequence. These results underscore the key role of interfacial strain and nanoscale magnetic disorder in tailoring the vortex-pinning landscape and enhancing the functional potential of YBCO/LSMO heterostructures for superconducting spintronic and hybrid quantum devices. • High-quality c-axis-oriented YBCO and YBCO/LSMO films were grown on LAO via pulsed laser deposition. • Interfacial strain produces tensile strain in YBCO and compressive strain in LSMO. • YBCO/LSMO shows ~4 K T sc suppression and diamagnetic fluctuations up to 120 K. • Strong SC–FM coupling enhances magnetoresistance and yields a triple-crossover J c (H) and F p (H). • Dew-Hughes analysis reveals interfacially driven δT sc , δℓ, and mixed pinning that reshape vortex behavior.