Critical current density of strained multilayer thin films of Nd _1.83Ce_0.17CuO_x/YBa₂Cu ₃O_7-δ

The superconducting transport properties of strained multilayer thin films of YBa2Cu3O7-δ/Nd1.83Ce 0.17CuOx, grown heteroepitaxially by laser ablation deposition, are reported. For individual layer thicknesses below a critical layer thickness of about 250 Å, coherency strain removes the orthorhombic distortion in the YBa2Cu3O7-δ layers and makes them twin-free. Zero-field critical current densities as high as 1.1×107 A/cm2 at 77 K have been measured for the YBa2Cu3O7-δ layers. Flux pinning energies at zero temperature and zero magnetic field in the range of 80-140 meV have been found.