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

The dielectric and pyroelectric performances of 91.5Na[Formula: see text]Bi[Formula: see text]TiO 3 –8.5K[Formula: see text]Bi[Formula: see text]TiO 3 lead-free single crystal were investigated. The depolarization temperature of the crystal is about 153[Formula: see text]C. Among the [Formula: see text]001[Formula: see text], [Formula: see text]110[Formula: see text], and [Formula: see text]111[Formula: see text] crystallographic orientations, the [Formula: see text]111[Formula: see text]-oriented crystal possesses the highest pyroelectric coefficient and the largest figures of merit, and the values of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]are 5.63× 10[Formula: see text] C/m 2 ⋅ K, 0.06 m 2 /C, and 21.5 [Formula: see text]Pa[Formula: see text] for the [Formula: see text]111[Formula: see text]-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 [Formula: see text] value of [Formula: see text] decreases from 18[Formula: see text]C to 103 [Formula: see text]C.