Correlations between structure and microwave dielectric properties of Co doped MgMoO4 ceramics. Issue 14 (1st October 2020)

• Record Type: Journal Article
• Authors: Bian, Wenjie; Lu, Xiaochi; Wang, Yan; Zhu, Haikui; Chen, Tao; Ta, Shiwo; Zhang, Qitu
• Is Part Of: Ceramics international. Volume 46:Issue 14(2020)
• Page Start: 22024
• Page End: 22029
• Publication Date: 2020-10-01
• Subjects: Disordered distribution -- MoO4 tetrahedron -- Microwave dielectric properties; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.05.187
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Mg1- x Co x MoO4 ( x = 0.01–0.15) ceramics were prepared by traditional solid-state methods. The phase composition, crystalline structure, micromorphology, and microwave dielectric properties of Mg1- x Co x MoO4 ceramics were comprehensively studied. Mg1- x Co x MoO4 ceramics present monoclinic wolframite structures from x = 0.01 to x = 0.15 with Co occupying the Mg-site. With the addition of Co 2+, ε r of Mg1- x Co x MoO4 ceramics increase. Q × f is maximal at 5 mol% Co 2+ content. The Mg0.95 Co0.05 MoO4 ceramic exhibits an optimal microwave dielectric property: ε r = 7, Q × f = 59247 GHz, τ f = −68 ppm/°C. The Q × f values increase by 20% compared with the pure MgMoO4 ceramics (~49149 GHz). Doping Co 2+ effectively promotes the densification of ceramics and increases ε r and Q × f . However, when the Co content exceeds 5 mol%, the decreased packing fraction and disorder distribution of ions contribute to the increase in dielectric losses. The correlations between Co 2+ substitution and wolframite structure have been discussed by Raman spectroscopy, FT-IR spectroscopy and Rietveld refinement.