Preparation Of YBCO/LNO/YBCO Trilayer By Sol-get Method

The multilayer structure with YBa2Cu3O7-x(YBCO)film as base electrode is a prospect candidate in the field of microelectronics.However,in the preparation process of YBCO multilayer,It is weak of some defects exist in the as-prepared films and the repeatability of the processes.The trilayer structure of YBCO/LNO(LaNi03)/(YBCO)was prepared using sol-gel method,and the trilayer was also patterned by combining the chemical decoration technology.At first,during the process of preparing YBCO films using a low-fluorine sol-gel method,we can obtain YBCO films with good superconductivity(Jc>1 MA/cm2)in a wide temperature range of 700?800 ? by altering the oxygen atmosphere during firing YBCO films.And there is an optimal oxygen partial pressure at each firing temperature.In them,Jc of the YBCO film is highest,which is near to 10 MA/cm2,at the condition of 775 0C and 78 Pa.Secondly,the heat treatment process of LNO films on LAO substrate was determined and found that LNO films present a good orientation and the surface is dense when the heat-treatment temperature is 750? and the oxygen partial pressure is 4 KPa.The bilayer films LAO substrates/YBCO(800?)/LNO(750?)and LAO substrates/LNO(750?)/YBCO(740?)were prepared in the manner of decreasing heat-treatment temperature layer by layer.The results of to and cp scan show that the two kinds of bilayer structures present a good biaxial-texture characteristic.Then basing the process above,LAO substrates/YBOO(800?)/LNO(750?)/YBCO(740?)trilayer was prepared by decreasing the firing temperature of subsequent films layer by layer.The obtained trilayer not only present a perfect biaxial-texture characteristic but also LNO films are grown on YBCO films with the mariner of cubic on cubic.And the interface between YBCO and LNO films is sharp,and no obvious interdiffusion is observed.Lastly,the crossover of YBCO/LNO/YBCO trilayer was obtained by combination of sol-gel and chemical decoration using the heat treatment process above,which can be a new scheme for high-temperature superconducting Josephson junction.