Dielectric properties of nanoparticulate Ba2EuZrO5.5 perovskite at microwave frequencies

Abstract

Dielectric properties of a complex perovskite material, Ba2EuZrO5.5, which was proposed as a suitable substrate for high TC superconducting films [R. Jose et al., J. Mater. Res., 15, 2125 (2000)], were measured in the frequency range from 0.47 to 26 GHz and in the temperature range from 77 to 350 K. In the present research, sintered bulk Ba2EuZrO5.5 material composed of nanocrystallites was used. The dielectric constant: ε′=32,25±0.3% was measured at 300 K, and the material was found to be rather lossy with tan δ close to 10−2. The temperature measurements show unusual behavior of the dielectric properties. In the range from 100 to 250 K, a considerable increase of the dielectric constant and losses were observed. This effect might be due to the tilting of B(B′)O6 octahedra commonly found in complex perovskite materials. Due to such behavior, the applications of Ba2EuZrO5.5 as a substrate for YBCO and BISCCO superconductors at high and microwave frequencies should be rather ruled out.