Crystal structure and dielectric properties of Mn-substituted Bi1.5Zn1.0Nb1.5O7 pyrochlore ceramics as temperature stable LTCC material

As a potentially attractive candidate of LTCC material, (Bi1.5Zn0.5−xMnx)(Zn0.5Nb1.5)O7 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics with improved temperature coefficient of the dielectric constant were synthesized by a conventional mixed oxide route. The relations between the microstructure and dielectric properties of the specimens were investigated systematically. Microscopic analysis showed that all the samples maintained the (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 phase. The variation of the unit cell volumes contributed to the shift of the peaks caused by the chemical substitution of ions. The temperature coefficient of the dielectric constant of (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 increased remarkably by Mn2+ substitution, but dielectric constant varied slightly while the dielectric loss increased steadily. The (Bi1.5Zn0.5−xMnx)(Zn0.5Nb1.5)O7 ceramic with x = 0.5 satisfied the EIA specification NP0 and exhibited excellent dielectric properties of εr = 132, tanδ = 2.45 × 10−3, τε = −17 ppm/°C with the low-firing temperature of 950 °C.