Microwave dielectric properties of (1-x) BiVO4–xLn2/3MoO4 (Ln=Er, Sm, Nd, la) ceramics with low sintering temperatures

A series of microwave dielectric ceramics of (1-x) BiVO4 -xLn2/3MoO4 (Ln = Er, Sm, Nd and La; x = 0.06, 0.08, 0.10) sintered below 900 °C were prepared via solid-state reaction. As the x values increase, the monoclinic scheelite continuously changes to a tetragonal structure at x = 0.10. The incorporation of Ln2/3MoO4 into the BiVO4 matrix increases the product (Q × f) of quality factor (Q) and resonance frequency (f), and temperature coefficient (τf), but lowers the dielectric constant (εr). Microwave dielectric ceramics with low sintering temperatures (<900 °C) are obtained: εr of ~71.1, 81.6, 75.6 and ~75.3; Q × f values of ~8292, 5508, 8695 and 9043 GHz; τf of ~ −51, 134, 149 and 158 ppm/°C, for 0.94BiVO4–0.06Er2/3MoO4, 0.92BiVO4–0.08Sm2/3MoO4, 0.9BiVO4–0.1Nd2/3MoO4 and 0.9BiVO4–0.1La2/3MoO4 ceramics, respectively. Moreover, (1-x) BiVO4 -xLn2/3MoO4 (Ln = Er, Sm, Nd and La; x = 0.06, 0.08 and 0.10) ceramics are chemically compatible with both Ag and Cu powders at their sintering temperatures. The series of microwave dielectric ceramics might be potential candidates for low temperature co-fired ceramics (LTCC) technology applications.