Synthesis and characterization of rare-earth barium antimonates, a new group of complex perovskites suitable as substrates for YBa2Cu3O7-δ films

A new group of complex perovskites, REBa2SbO6 (where RE = Pr, Sm, and Gd), have been synthesized and sintered as single phase materials by the solid state reaction method. These materials are found to be isostructural and to have a complex cubic perovskite structure. X-ray diffraction and resistivity measurements have shown that there is no detectable chemical reaction between YBa2Cu3O7-δ and REBa2SbO6 even under severe heat treatment at 950 degrees C and that the addition of REBa2SbO6 up to 20 vol% in YBa2Cu3O7-δ shows no detrimental effect on the superconducting properties of YBa2Cu3O7-δ. The dielectric constant and loss factor values of the sintered REBa2SbO6 materials are in a range suitable for their use as substrates for microwave applications. Thick films of YBa2Cu3O7-δ fabricated on polycrystalline REBa2SbO6 substrates give superconducting zero resistivity transition temperature Tc(0) = 92 K, indicating the suitability of these materials as substrates for YBa2Cu3O7-δ films