Composition, dc bias and temperature dependence of pyroelectric properties of ⟨111⟩-oriented (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 crystals

The pyroelectric properties of < 111 >-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 degrees C showing little thermal hysteresis. At room temperature, PMN-0.21PT crystal has the highest pyroelectric coefficient of 17.9 x 10(-4) C/m(2) K. However, the best pyroelectric performance can be achieved for PMN-0.26PT crystal, with the voltage responsivity and detectivity figures of merit F-v and F-d of about 0.11 m(2)/C and 15.3 x 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 < 111 >-oriented PMN-xPT crystals a promising candidate for room-temperature infrared detectors and thermal imagers. (c) 2005 Elsevier B.V. All rights reserved.