Liquid phase epitaxy of crystalline REBa 2Cu 3O 6+δ films on reactive substrates using the BaF 2BaOCuO flux

Abstract

Phase relations concerning the crystal formation of YBa 2Cu 3O 6+δ and NdBa 2Cu 3O 6+δ phases from the BaF 2BaOCuO flux have been investigated by the liquid phase epitaxial technique on various substrates. As the amount of BaF 2 in the solution increases, the temperature of REBa 2Cu 3O 6+δ (RE = Y, Nd) formation decreases down to about 920°C not only in the Y system but also in the Nd system. The decrease of the growth temperature allows us to form liquid phase epitaxial thick films on the reactive substrates such as yttria-stabilized zirconia and SrTiO 3, which rapidly react with REBa 2Cu 3O 6+δ and the melt of barium cuprate flux at high temperatures. Our studies have also revealed that the seed layer pre-deposited on the substrates plays an important role in epitaxial growth of REBa 2Cu 3O 6+δ to form thick films on these substrates.