Weibai Bian

All chemical solution deposition of textured YBa2Cu3O7?x/Y0.2Ce0.8O2/La2Zr2O7 multilayer films on biaxially textured NiW tape

Biaxially textured La2Zr2O7 (LZO) single buffer layer, Y0.2Ce0.8O2 (YCO) single buffer layer, and YCO/LZO bilayer buffer layer are prepared on NiW tapes using chemical solution deposition technique. All the buffer layers are of good in-plane and out-of-plane texture. The introduction of a YCO cap layer on the LZO buffer layer improves the surface quality of the films. YBa2Cu3O7−x (YBCO) films are then prepared on these buffer layers using our recently developed low-fluorine solution route. Purely c-oriented YBCO films with good in-plane and out-of-plane texture are obtained on the YCO/LZO bilayer buffer layers. The YBCO/YCO/LZO/Ni stack prepared using all chemical solution routes shows a high Tc over 90 K, a sharp transition temperature ΔT = 0.8 K, and a Jc of 0.7 MA cm−2(at 77 K, 0T).

Effect of La/Zr ratio in the precursor solution on the properties of La2Zr2O7 and CeO2/La2Zr2O7 films

La2Zr2O7 (LZO) films and CeO2/LZO composite films were prepared on the biaxially textured NiW tapes using metal organic deposition method. Effect of molar ratio of La/Zr in the precursor solution on the texture and surface morphology of LZO films and composite CeO2/LZO films was investigated systemically. It was found that the content of lanthanum played an important role in the orientation control of the LZO film. Finally, the LZO film with ratio of La/Zr = 1.1/1 was obtained with the best properties as compared to others. And highly textured LZO-11 and CeO2/LZO-11 films with smooth surface were obtained on the NiW tape. YBa2Cu3O7-x (YBCO) films with enhanced critical current density (Jc) were obtained on the optimized CeO2/LZO buffer layer.Graphical AbstractThe LZO films were prepared from different LZO solutions with different molar ratio of La/Zr, and the effects of the La/Zr ratio on the texture and surface morphology of LZO films were systemically investigated. The results confirmed that the content of lanthanum in solution was closely related to the orientation control of the LZO film. When the ratio of La/Zr was smaller than La/Zr = 1, the pure (l00)-oriented phase was not achieved. When that was larger than La/Zr = 1.2, in spite of the pure (l00)-oriented phase, the more lanthanum content increased the lattice parameter of the LZO films. In summary, the ratio of La/Zr = 1.1 was the optimized ratio for the fabrication of LZO film due to the best texture and surface morphology.

Resistive Switching Characteristics of Flexible TiO 2 Thin Film Fabricated by Deep Ultraviolet Photochemical Solution Method

A novel ultraviolet photochemical method was used to prepare TiO2 resistive-switching films. Amorphous TiO2 films were formed on flexible indium-tin oxide (ITO) coated polyethylene terephthalate (PET) substrates by deep ultraviolet irradiation at 150 °C. A Pt/TiO2/ITO/PET device was then fabricated to investigate bipolar resistive switching of the films for potential application in non-volatile memories. The ratio of on-state to off-state currents was measured, and a good value of 1000 was obtained. The retention and switch-cycling characteristics of the device were investigated for different bending radii. The resistive switching behavior of the flexible device remained stable after 600 cycles of electrical switching and 1000 cycles of bending.

High Critical Current Density of YBa 2 Cu 3 O 7−x Superconducting Films Prepared through a DUV-assisted Solution Deposition Process

Although the solution deposition of YBa2Cu3O7−x (YBCO) superconducting films is cost effective and capable of large-scale production, further improvements in their superconductivity are necessary. In this study, a deep UV (DUV) irradiation technique combined with a low-fluorine solution process was developed to prepare YBCO films. An acrylic acidic group as the chelating agent was used in the precursor solution. The acrylic acidic group was highly sensitive to DUV light at 254 nm and significantly absorbed UV light. The coated gel films exposed to DUV light decomposed at 150 °C and copper aggregation was prevented. The UV irradiation promoted the removal of the carbon residue and other by-products in the films, increased the density and enhanced the crystallinity and superconductivity of the YBCO films. Using a solution with F/Ba = 2, YBCO films with thicknesses of 260 nm and enhanced critical current densities of nearly 8 MA/cm2 were produced on the LaAlO3 (LAO) substrates.