Adjustable dielectric properties of Li2CuxZn1−xTi3O8 (x=0 to 1) ceramics with low sintering temperature

Single-phase dielectric ceramics Li2CuxZn1−xTi3O8 (x=0-1) were synthesized by the conventional solid-state ceramic route. All the solid solutions adopted Li2MTi3O8 cubic spinel structure in which Li/M and Ti show 1:3 order in octahedral sites whereas Li and M are distributed randomly in tetrahedral sites with the degree of Li/M cation mixing varying from 0.5 to 0.3. The substitution of Cu for Zn effectively lowered the sintering temperatures of the ceramics from 1050 to 850 °C and significantly affected the dielectric properties. As x increased from 0 to 0.5, τf gradually increased while the dielectric constant (εr) and quality factor value (Q×f) gradually decreased, and a near-zero τf of 1.6 ppm/°C with εr of 25.2, Q×f of 32,100 GHz could be achieved for Li2Cu0.1Zn0.9Ti3O8 ceramic sintered at 950 °C, which make it become an attractive promising candidate for LTCC application. As x increases from 0.5 to 1, the dielectric loss significantly increases with AC conductivity increasing up to 2.3×10−4 S/cm (at 1 MHz).