Composition, dc bias and temperature dependence of pyroelectric properties of 〈1 1 1〉-oriented (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 crystals

The pyroelectric properties of 〈1 1 1〉-oriented (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) crystals with x = 0.21, 0.26, 0.30 and 0.33 have been investigated. The pyroelectric coefficients were measured using a dynamic technique under various thermal and electrical conditions. The pyroelectric coefficients decrease with increasing PT content and dc bias, and nearly increase linearly with increasing temperature from 20 to 55 °C showing little thermal hysteresis. At room temperature, PMN–0.21PT crystal has the highest pyroelectric coefficient of 17.9 × 10−4 C/m2 K. However, the best pyroelectric performance can be achieved for PMN–0.26PT crystal, with the voltage responsivity and detectivity figures of merit Fv and Fd of about 0.11 m2/C and 15.3 × 10−5 Pa−1/2, respectively, over a wide range of frequency from 50 to 30 kHz. The results demonstrate that superior pyroelectric performance makes 〈1 1 1〉-oriented PMN–xPT crystals a promising candidate for room-temperature infrared detectors and thermal imagers.