Effects of (Al0.5Nb0.5)4+ on the phase constitution, microtopography, and microwave dielectric properties for BaZn2Ti4O11 ceramics

In this article, we synthesized BaZn1.98Cu0.02Ti4O11 ceramics co-doped with a complex ion (Al0.5Nb0.5)(4+), resulting in improved microwave characteristics. Our analysis revealed that all BaZn1.98Cu0.02Ti4-x(Al0.5Nb0.5)(x)O-11 (BZCTAN) samples formed the main phase of BaZn2Ti4O11. Increasing the number of dopants increased the bulk density, which in turn increased the dielectric constant (epsilon(r)) and temperature coefficient of the resonance frequency (tau(f)) values consistently. The quality factor (Qxf) showed a tendency to increase and then decrease as the x value increased. Results indicated that a moderate content of (Al0.5Nb0.5)(4+) can improve the Qxf value. However, an excess of (Al0.5Nb0.5)(4+) resulted the formation of the second phase of Ba3Nb4Ti4O21, which reduced the grain size and the Qxf value in BZCTAN samples. At last, the BaZn1.98Cu0.02Ti3.8(Al0.5Nb0.5)(0.2)O-11 ceramic sample sintered at 1170 degrees C demonstrated good microwave dielectric properties of e(r) = 30.6, Qxf = 53,126 GHz, and tau(f) = - 32.3 ppm/degrees C.