Time-domain terahertz transmission absorption of (Ca0.5+xSr0.5-x)[(Al0.5Nb0.5)0.5Ti0.5]O3 complex perovskite

The phase assemblage and dielectric properties of (Ca0.5+xSr0.5-x)[(Al0.5Nb0.5)(0.5)Ti-0.5]O-3 ceramics (abbreviated as CSANT hereafter) in Terahertz waveband were investigated. The CSANT complex perovskite was unstable at Ca2+-rich composition, a secondary phase were easily segregated in x >=-0.05 region. The main perovskite phase CSANT crystallized in Fm3m cubic symmetry in the composition range of x <=-0.1, however, it transited to Pbnm orthorhombic space group after x=-0.1 due to the antiphase tilting of oxygen octahedra. As x further increased to x=0.2, or the tolerance factor decreased to 0.9785, A-site Ca2+/Sr2+ cations antiparallel displacements also appeared. The dielectric absorption property of CSANT ceramics in THz frequency range was investigated using time-domain transmission spectrum technology and was correlated to their microstructures. The compositional dependence of the power absorption property of CSANT ceramics exhibited a monotonous variation in 0.1 similar to 2.5THz frequency. A lowest THz power absorption ceramic could be obtained in CSANT compounds at x=0.3 when sintered at 1500 degrees C for 4hrs.