Preparation Of YBCO/Y₂O₃/YBCO Trilayer Films And Titmultilayer Microstructures

YBCO/interlayer/YBCO three-layer films has important application value in the preparation of superconducting electronic devices such as Josephson junction,superconducting capacitor and planar flux converter due to its unique electromagnetic transport characteristics.Usually in these applications,it is necessary to process them into specific micro-graphics structure to meet the requirements of performance and volume structure.Because of the characteristics of YBCO,the superconductivity of YBCO is often degraded by traditional etching process,and the existing micro-fabrication methods are difficult to fabricate composite structures with multi-layer micro-patterns.In view of this problem,this paper intends to study the preparation and superconducting electrical properties of YBCO/Y₂O₃/YBCO three-layer films and multilayer micropatterned structure by means of photosensitive sol-gel method through micro patterning and layer by layer sintering technology.The feasibility of fabrication of superconducting microelectronic devices is also explored.The main research work is as follows:（1）YBCO sol and Y₂O₃ sol with ultraviolet sensitivity were prepared by adding photosensitive modifier BzAcH.The photosensitive mechanism of YBCO and Y₂O₃ sol was analyzed by UV and IR spectra.The effects of drying time,exposure time,type of detergent and thickness of gel film on the processing technology of micro graphics were studied.A YBCO grating with a line width of 10 μm and a Y₂O₃ grating structure with a period of 10 μm and 2 μm were fabricated.（2）YBCO/Y₂O₃/YBCO three-layer films were prepared on LAO substrates by layer-by-layer processing and heat treatment with decreasing temperature gradient.The properties of YBCO and Y₂O₃ thin films were tested.The results show that YBCO thin films on both sides of Y₂O₃ have good c-axis growth orientation and superconductivity.The Ⅰ-Ⅴ curves between the three layers show that the Ⅰ-Ⅴ curves are linear with the increase of the thickness of the insulation layer in the three layers,which indicates that the conductivity of the three layers follows the ohmic conductivity.（3）On the basis of the above research,a closed superconducting planar flux converter multi-turn input coil with a total length of 7 mm,a width of 25 μm and a total of 4 turns has been further fabricated by means of multiple pattern embedding.The superconducting transition temperature T_c,onset of the closed loop coil are about 92K.The Ⅰ-Ⅴ curve shows that the critical current I_c value decreases with the increase of temperature.The Ⅰ-Ⅴ curve measured at 50K shows that the critical current is about 0.01 mA.