BiFeO3 tailored low loss M-type hexaferrite composites having equivalent permeability and permittivity for very high frequency applications

• Published in: Journal of alloys and compounds Vol. 630; pp. 48 - 53
• Main Authors: Peng, Yun, Wu, Xiaohan, Chen, Zhongyan, Liu, Weihu, Wang, Fan, Wang, Xian, Feng, Zekun, Chen, Yajie, Harris, Vincent G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.05.2015
• Subjects: Low loss; M-type hexaferrite; Solid-state reaction method; Solid-state reaction method; Low loss; M-type hexaferrite
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2015.01.026

•Moderate Bi2O3 can improve the sintering process of the hexaferrites.•Bi2O3 enables the formation of a secondary phase, which was verified to be BiFeO3.•The BFO phase reduces both magnetic and dielectric losses.•The ferrites with BFO inclusions reveals equivalent μ′ to ε′ with low loss factor.•The results have revealed potential to make antennas smaller at lower costs. Co–Ti substituted M-type hexaferrite composites, consisting of Ba(CoTi)1.2Fe9.6O19 with various amounts of Bi2O3 (0–8wt%), were successfully synthesized by conventional ceramic processes. The effects of Bi2O3 upon the composite microstructure, magnetic properties, and magnetic and dielectric properties sintered at low temperatures were systematically investigated. The present studies aim to develop magneto-dielectric materials possessing equivalent values of permeability and permittivity, as well as low magnetic and dielectric losses, which allow for miniaturizing efficient antennas at the very high frequency band (VHF, 30–300MHz). The present experiments show that addition of BiFeO3, observed in the polycrystalline hexaferrite composites, acts to reduce loss factors (i.e., tan δμ/μ′=0.014, tan δε/ε′=0.00071) while concomitantly retaining high and equivalent values of permeability and permittivity (i.e., μ′∼12 and ε′∼12 at 300MHz).