Investigation of the electrical properties of (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals with special reference to pyroelectric detection

Abstract

The pyroelectric properties of relaxor-based ferroelectric single crystals (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) with 0.13 ⩽ x ⩽ 0.40 were investigated for infrared detectors and imagers. The optimized compositions, crystallography orientations and thermal treatment temperature have been confirmed. The results show that [1 1 1] oriented rhombohedral PMN–xPT with 0.26 ⩽ x ⩽ 0.28 possess superior pyroelectric performances with high figures of merit (FOM) for the current responsivity Fi ∼ 600 pm V−1, voltage responsivity Fv ∼ 0.11 m2 C−1 and detectivity Fd ∼ 15 × 10−5 Pa−1/2 at room temperature. The pyroelectric properties are relatively independent of the temperature between 15 and 70 °C while they dramatically degrade with T > 80 °C. Future infrared detector and imager designs can rely on PMN–xPT single crystals with 0.26 ⩽ x ⩽ 0.28 offering outstanding pyroelectric performance under operational conditions of T < 70 °C. [0 0 1] oriented PMN–xPT single crystals with x ⩾ 0.37 offer relatively lower FOM but higher phase transition temperature and weaker temperature dependence of the pyroelectric properties. Therefore, it is required to select a composition of PMN–xPT single crystals for device application according to the application environment and the performance requirement.