Microwave dielectric properties of BaCu2-xMnxSi2O7 (x=0-0.04) ceramics

BaCu2-xMnxSi2O7 (x = 0-0.04) microwave dielectric ceramics were synthesized through solid-state reaction method. Effects of substitution with Mn2+ ions for Cu2+ ions on phase composition, crystal structure, and microwave dielectric properties of BaCu2Si2O7 ceramics were investigated in detail. XRD results revealed that BaCu2Si2O7 solid solution with orthorhombic structure was formed in all samples. Under combined action of porosity and ionic polarizability, epsilon(r) values of BaCu2-xMnxSi2O7 ceramics showed a tendency of first increasing and then decreasing with doping content of Mn2+ ions. The variation in Q(f) was attributed to the change of porosity and total lattice energy. The decrease in average bond energy contributed to falling tau(f) values. Besides, Raman shifts that resulted from stretching vibration of Cu-O bond exhibited an opposite trend compared with epsilon(r). FWHM of Raman peak for Si-O bond varied inversely with the Q(f) of BaCu2-xMnxSi2O7 ceramics. The optimal properties were attained for BaCu2-xMnxSi2O7 (x = 0.02) ceramics sintered at 1020 degrees C: epsilon(r) = 8.12, Q(f) = 54,692 GHz, and tau(f) = - 29.5 ppm/degrees C.

Automated summary

BaCu2-xMnxSi2O7 microwave dielectric ceramics were synthesized, and the effects of Mn2+ substitution for Cu2+ on the phase composition, crystal structure, and microwave dielectric properties were investigated. The results showed that the dielectric constant of the ceramics exhibited an increasing and then decreasing trend with increasing Mn2+ doping content, while the change in Q(f) was related to the porosity and total lattice energy.