Pyroelectric properties of 91.5Na0.5Bi0.5TiO3–8.5K0.5Bi0.5TiO3lead-free single crystal

Abstract

The dielectric and pyroelectric performances of 91.5[Formula: see text][Formula: see text]TiO3–8.5[Formula: see text][Formula: see text]TiO3 lead-free single crystal were investigated. The depolarization temperature of the crystal is about 153 [Formula: see text]C. Among the <001>, <110>, and <111> crystallographic orientations, the <111>-oriented crystal possesses the highest pyroelectric coefficient and the largest figures of merit, and the values of [Formula: see text], [Formula: see text], and [Formula: see text]are 5.63×10[Formula: see text] C/m2 •K, 0.06 m2/C, and 21.5 [Formula: see text]Pa[Formula: see text] for the <111>-oriented crystal at room temperature. The [Formula: see text]and [Formula: see text]exhibit weak frequency dependence in the range of 100–300 Hz. With the increase of the temperature, the value of [Formula: see text]increases, while the value of [Formula: see text] decreases from 18 [Formula: see text]C to 103 [Formula: see text]C.