Temperature dependent Raman spectroscopic studies on microwave dielectrics Sr(AL_1/2Ta_1/2)O₃and Sr(Al_1/2Nb_1/2)O₃

Abstract

Abstract Complex oxide perovskites, namely strontium aluminum tantalum oxide (SAT) and strontium aluminum niobium oxide (SAN) were recently investigated to be potential substrate materials for HTSC films in microwave applications. Single crystals (disordered phase) were prepared by laser heated pedestal growth technique (LHPG) and ordered ceramics samples were prepared by conventional sintering technique. We report Raman vibrational spectrum studies on them for the first time. Order-disorder effects of (A1, Ta) and (Al, Nb) sites were studied by comparing Raman spectra of single-crystal samples with ceramic samples. Influences of B sites (Ta and Nb) on O-O modes are discussed in relation to their dielectric properties.