Preparation And Properties Of Cruciform YBCO/Bi-2212 Superconducting Heterojunction

High-temperature superconducting heterojunctions with Josephson effect have broad application prospects in quantum interference devices,terahertz sources and detectors.At present,the preparation of high-temperature superconducting heterojunctions has problems such as difficulty in the thickness of the intermediate transition layer,low repeatability,and damage to the performance of the film due to the etching method incorporated in the preparation process.Therefore,it is necessary to study a method that does not damage the performance of the superconducting Josephson junction and achieves the required thickness of the intermediate layer.In this paper,the photosensitive sol-gel method to prepare YBa2Cu3O7-?/Bi2Sr2Ca1Cu2O8-? superconducting heterojunction,and the strain layer generated between the crystal lattice of YBCO and Bi-2212 replaces the intermediate layer to realize Joseph The forest effect has specifically carried out the following work:(1)The photosensitivity of Bi-2212 sol was studied by using BzAc as a chelating agent.Compared with acrylic acid as a chelating agent,the photosensitivity of the sol was increased by 23%,and the quality of the fine patterns was improved.The Bi-2212 fine patterns were heat-treated,A fine patturn of Bi-2285 with a superconducting transition temperatnre Tc of 85K was obtained.(2)YBCO/Bi-2212 superconducting heterojunction was prepared at different heat treatment temperatures.When the upper and lower heat treatment temperatures were 830? and 800?,the YBCO/Bi-2212 superconducting heterojunction The junction pcrformance is good.By testing the different positions of the YBCO/Bi-2212 superconducting heterojunction,three different types of Josephson junctions can be obtained:grain boundary junction,step junction,YBCO/strain layer/YBCO junction.(3)YBCO/Bi-2212 superconducting heterojunctions with different junction areas are prepared,and the junction area affects the I-V characteristic curves of the three types of Josephson junctions.For the interface junction and step junction formed by YBCO/Bi-2212 superconducting heterojunction,it is found that when the junction area is 100*100 ?m2,the Josephson effect with hysteresis appears in the I-V characteristic curve.When the junction area decreases Up to 100*10 ?m2,10*100?m2,10*10?m2,it does not have the Josephson effect.For the YBCO/strained layer/YBCO junction formed by the YBCO/Bi-2212 superconducting heterojunction,when the junction area is 100*100 ?m2,it has the Josephson effect,when the junction area is 100*10 ?m2,10*100 ?m2,The I-V characteristic curve is realized as the characteristic of the SIS tunnel.When the junction area is 10*10 ?m2,the I-V characteristic curve shows the characteristic of SNS proximity effect.