Electrodeposited Biaxially Textured Buffer Layers for YBCO Superconductors

Abstract

Non-vacuum electrodeposition (ED) was used to prepare simplified Gd ₂ O ₃ /Gd ₂ Zr ₂ O ₇ and CeO ₂ /Gd ₂ Zr ₂ O ₇ buffer layers on a Ni-W substrate. Post-annealing conditions of electrodeposited precursor films were optimized to obtain high-quality biaxially textured buffer layers. The buffer layers were characterized by X-ray diffraction, optical profiling, and transmission electron microscopy (TEM). The effect of the cap layer thickness on the surface morphology and texture of the buffers was also studied. The microstructure of CeO ₂ /Gd ₂ Zr ₂ O ₇ was analysed and compared to Gd ₂ O ₃ /Gd ₂ Zr ₂ O ₇ . The high-resolution TEM shows biaxially textured crystalline elctrodeposited Gd ₂ O ₃ and CeO ₂ cap layers on the electrodeposited Gd ₂ Zr ₂ O ₇ layers without any defects. YBa ₂ Cu ₃ O _7-delta (YBCO) superconductor was deposited by pulsed laser deposition (PLD) on the simplified ED-Gd ₂ O ₃ /Gd ₂ Zr ₂ O ₇ and ED-CeO ₂ /Gd ₂ Zr ₂ O ₇ buffers. Transport current density of 3.3 MA/cm ² at 77 K was obtained for PLD YBCO deposited on ED-Gd ₂ O ₃ /Gd ₂ Zr ₂ O ₇ buffer layers.