The effect of B-site ions on crystal structure evolution and microwave dielectric properties of gillespite-type SrCu0.95B0.05(B2+: Cu, Co, Mn, Ni, Mg, Zn)Si4O10

Gillespite-type SrCu 0.95 B 0.05 (B 2+ :Cu,Co,Mn,Ni,Mg,Zn)Si 4 O 10 (SCBS) ceramics were prepared by high-temperature solid-state method. Their microwave dielectric properties and crystal structure evolution were studied by P–V-L theory, bond valence model, and X-ray photoelectron spectroscopy. Varying B 2+ ion changed ionic polarizability and bond ionicity, causing dielectric constant ε r of SCBS to change. The change in quality factor Q  ×  f was explained by lattice energy, oxidation state of Cu, and internal strain/fluctuation. The temperature coefficient of resonator frequency τ f was regulated by B–O bond length and valence. The optimal microwave dielectric properties were exhibited by SrCu 0.95 Mn 0.05 Si 4 O 10 after sintering at 1050 °C: ε r ∼5.8 ± 0.03, Q  ×  f ∼65,589 ± 2611 GHz (@15.8 GHz), and τ f  ∼ -50 ± 4 ppm/°C. These materials show great potential application prospects for 5G/6G wireless communication.