Liquid-phase epitaxy processing of RBa₂Cu₃O7−δ

The study of processing by liquid-phase epitaxy (LPE) is promising because the LPE process can provide rapid and thick film formation of RBa 2 Cu 3 O 7- (RBCO). The growth rate can reach 10 µm min -1 and films of more than 5 µm in thickness formed by the LPE process show a high critical current density of about 1 MA cm -2 . To apply this process widely, a decrease of the processing temperature is required because it gives rise to a reaction between the solution and many of the substrate materials. Film formation on yttria-stabilized ZrO 2 and silver substrates, which are more reactive than other materials such as MgO or SrTiO 3 , has been achieved by decreasing the temperature to below 920 °C, with the addition of BaF 2 in the solution. This paper describes processing by LPE for forming RBCO films and efforts for practical application towards coated conductors and RF electronic devices.