Microwave dielectric properties of Al-doped Ba4(Sm, Nd)9.33Ti18O54 ceramics added with TiO2 and sintered in oxygen. Issue 9 (1st May 2022)

• Record Type: Journal Article
• Authors: Ma, Zhiyu; Guo, Weijia; Yue, Zhenxing
• Is Part Of: Ceramics international. Volume 48:Issue 9(2022)
• Page Start: 12906
• Page End: 12913
• Publication Date: 2022-05-01
• Subjects: Microwave dielectric ceramics -- Titanates -- Defects; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.01.163
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: TiO2 -added Ba4 (Sm0.65 Nd0.35 )9.33 Ti17.75 Al0.33 O54 (BSNTA) ceramics were fabricated with a solid-state reaction method. Slight TiO2 addition increased the dielectric constant ( ε r ) of BSNTA ceramics and brought about a near-zero temperature coefficient of resonant frequency ( τ f ). Sintering in oxygen increased the density of TiO2 -added BSNTA ceramics and surprisingly concurrently improved the ε r and Q × f value. Thermally stimulated depolarization current (TSDC) measurements indicated that TiO2 addition introduced oxygen vacancies ( V O .. ) and Ti Ti ' − V O .. defect dipoles and that an oxygen-sufficient sintering atmosphere decreased the concentration of these defects and thus increased Q × f values. From the viewpoint of defect behaviors, this observation offered original insight into the mechanism by which the sintering atmosphere had impacts on the Q × f value of titanate ceramics. Satisfying dielectric properties ( ε r = 79.5, Q × f = 14, 840 GHz, τ f = 0 ppm/°C) were attained in oxygen-sintered BSNTA-0.6%TiO2 ceramics that might be suitable for the manufacture of miniature microwave devices such as filters and antennas.