Structural and dielectric properties of Ba2YbTaO6, Ba2YSbO6 and Ba2EuZrO5.5

Structural and dielectric properties of Ba2YbTaO6, Ba2YSbO6 and Ba2EuZrO5.5 perovskites are presented. Because these materials were suggested as prospective buffer layers and substrates for HTS electronic devices such as SIS structures etc., their chemical stability with YBa2Cu3O7−δ (YBCO) and Bi2Sr2CanCun+1Ox (n = 1, 2; BiSCCO) was examined up to processing temperatures of listed superconductors. All three materials were found to be chemically stable with both YBCO and BiSCCO. Moreover, addition of ca. 20% of these perovskites to YBCO did not have any detrimental effect on the transition temperature.Dielectric properties of all a.m. materials were determined with high accuracy by measuring resonant frequencies of completely filled dielectric cavities at frequencies up to 40 GHz and at temperatures from 60 K to 350 K. The dielectric permittivities for particular materials are as follows: Ba2YbTaO6 → ε′ = 29.4; Ba2EuZrO5.5 → ε′ = 30.8; Ba2YSbO6 → ε′ = 13.5. In microwave range all materials exhibit low or moderate losses. However, at temperatures where HTS materials enter into superconducting state (80–130 K), they exhibit some unusual features (a kind of a phase transition), which may either help or hamper their suggested applications in HTS electronics [J. Konopka, I. Wolff, S.J. Lewandowski, J. Appl. Phys. 72 (1992) 218].