Polycrystalline ${\rm MgB}_{2}$ Films on Flexible YSZ Substrates Grown by Hybrid Physical-Chemical Vapor Deposition
We report properties of polycrystalline MgB2 films deposited on thin flexible yttium-stabilized zirconia (YSZ) substrates by hybrid physical-chemical vapor deposition. The MgB2 films show a transition temperature of 38.9 K with a narrow superconducting transition (0.1 K). The self-field critical current density in the films reaches 107 A/cm2 at low temperatures. These properties do not change after repeated bending over a radius of 10 mm. Low microwave surface resistance comparable to those obtained in epitaxial MgB2 films on single-crystalline sapphire substrate was observed. The result shows promise of polycrystalline MgB2 films for applications in superconducting digital circuits as well as in coated conductor wires.