Freestanding La₂CuO₄/La_1.55Sr_0.45CuO₄ heterostructure membranes with high-T_C interface superconductivity

We report the fabrication of freestanding La₂CuO₄/La_1.55Sr_0.45CuO₄ (LCO/LSCO) heterostructure membranes, which were fabricated by selectively etching water-soluble Sr₃Al₂O₆ sacrificial layers from pulsed-laser-deposited heterostructures on SrTiO₃ substrates. Transport measurements reveal that these membranes exhibit superconducting behavior with an onset temperature of approximately 19 K. Comprehensive structural characterization using x-ray diffraction and scanning transmission electron microscopy demonstrates that the membranes retain excellent crystalline quality after release. The superconducting properties remain stable following mild post-annealing treatment under vacuum. This work establishes LCO/LSCO as a promising platform for developing flexible high-temperature superconducting interfaces, opening new possibilities for the development of flexible devices.