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 YBa₂Cu₃O_7-δ/Nd_1.83Ce _0.17CuO_x, 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 YBa₂Cu₃O_7-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 YBa₂Cu₃O_7-δ layers. Flux pinning energies at zero temperature and zero magnetic field in the range of 80-140 meV have been found.