Single buffer layers of either Gd2Zr2O7 (GZO) or La2Zr2O7 (LZO) with different thickness on highly textured Ni-W tapes were compared with respective to the application of YBa2Cu3O7-δ coated conductors. The supercondu...Single buffer layers of either Gd2Zr2O7 (GZO) or La2Zr2O7 (LZO) with different thickness on highly textured Ni-W tapes were compared with respective to the application of YBa2Cu3O7-δ coated conductors. The superconducting performances are improved as the buffer thickness of GZO or LZO increases up to a critical value, such as 310 and 240 nm, respectively. This suggests that a thin buffer layer is insufficient to prevent the Ni diffusion. If the buffer thickness increases further, the superconducting properties degrade, probably due to changes in the microstructure and degradation of the buffer texture. Comparing with LZO, the texture of GZO is hardly dependent on its thickness, due to smaller mismatch for its lattice with that of Ni-W. For both single buffered coated conductors, the superconducting transition temperatures are around 92 K with a transition width less than 1 K. Inductive measurement reveals that the critical current density (Jc) at 77 K in self-field, reaches 1.2 MA/cm2 and 0.77 MA/cm2 for GZO, and LZO, respectively. This implies that the single buffers of GZO and LZO are comparable to standard buffer architectures such as CeO2/YSZ/Y2O3 or CeO2/LZO, being promising for the process simplification and cost reduction.展开更多
基金National Natural Science Foundation of China (50702033 and 10774098)Ministry of Science and Technology of China ("863" Projects,.2009AA03Z204)+3 种基金Science and Technology Commission of Shanghai Municipality (08521101502)Innovation Funds for Ph. D. Graduates of Shanghai University(SHUCX101022)Shanghai Leading Academic Discipline Project (S30105)Project Based Personnel Exchange Programme with China and Germany (PPP)([2006]3139)
文摘Single buffer layers of either Gd2Zr2O7 (GZO) or La2Zr2O7 (LZO) with different thickness on highly textured Ni-W tapes were compared with respective to the application of YBa2Cu3O7-δ coated conductors. The superconducting performances are improved as the buffer thickness of GZO or LZO increases up to a critical value, such as 310 and 240 nm, respectively. This suggests that a thin buffer layer is insufficient to prevent the Ni diffusion. If the buffer thickness increases further, the superconducting properties degrade, probably due to changes in the microstructure and degradation of the buffer texture. Comparing with LZO, the texture of GZO is hardly dependent on its thickness, due to smaller mismatch for its lattice with that of Ni-W. For both single buffered coated conductors, the superconducting transition temperatures are around 92 K with a transition width less than 1 K. Inductive measurement reveals that the critical current density (Jc) at 77 K in self-field, reaches 1.2 MA/cm2 and 0.77 MA/cm2 for GZO, and LZO, respectively. This implies that the single buffers of GZO and LZO are comparable to standard buffer architectures such as CeO2/YSZ/Y2O3 or CeO2/LZO, being promising for the process simplification and cost reduction.
