Crystal Structure, Infrared Reflection Spectrum, and Improved Microwave Dielectric Characteristics of BaSmTiO Ceramics via One-Step Reaction Sintering.

High-k BaSmTiO ceramics with improved microwave dielectric characteristics were successfully fabricated using the one-step reaction sintering (RS) route. The sintering characteristics, microstructure, crystal structure, infrared reflection spectrum, and microwave dielectric characteristics of BaSmTiO ceramics prepared by the RS route were systematically investigated. Samples prepared by the RS route exhibited single-phase orthorhombic tungsten-bronze structure and dense microstructure at optimum sintering temperature. Compared with the conventional solid-state (CS) process, the BaSmTiO ceramics fabricated by the RS route presented a smaller temperature coefficient (TCF), a higher quality factor (), and a higher permittivity (). The improved microwave dielectric characteristics were highly dependent on the theoretical permittivity, atomic packing fraction, suppression of Ti, and Ti-site bond valence. Excellent combined microwave dielectric characteristics (TCF = -7.9 ppm/°C, = 9519 GHz, = 80.26) were achieved for BaSmTiO ceramics prepared by RS route sintered at 1400 °C, suggesting the RS route was a straightforward, economical and effective route to prepare high-performance BaSmTiO ceramics with promising application potential.