Temperature- and time-dependent properties of polycrystalline (Li,Na)NbO3 solid solutions

Pressure-sintered LixNa1−xNbO3 in the range 0.015⩽x⩽0.15 exhibits electromechanical properties amenable to high-frequency device applications with radial-frequency constants fR(r) between 1.75 and 1.95 kHz m, coupling coefficients up to 0.4, and permittivities between 100 and 200. The temperature and time dependencies of fR are shown to be strongly related to composition, where for x=0.12, the temperature coefficient between −40 and 80 °C is −2×10−4 °C−1 and the ageing coefficient is −2.5×10−3 per decade. The results are discussed in relation to composition and with respect to anomalies at phase transitions in (Li,Na)NbO3.