Dielectric and Pyroelectric Properties of 〈111〉‐Oriented Fe‐Doped 0.62Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 Single Crystals

Abstract

Fe‐doped 0.62Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 (PMN–0.38PT) single crystals were grown by a modified Bridgman technique. Two kinds of single crystals with different iron ion molar ratios, (i) 0.2 mol% and (ii) 1.0 mol%, were obtained. The effect of doping iron ions on the dielectric and pyroelectric properties of the 〈111〉‐oriented PMN–0.38PT single crystals was examined. The temperature of the permittivity maximum (Tm) exhibits no dispersion behavior and decreases with increasing doping concentration. The dielectric loss of the 0.2 mol% Fe‐doped PMN–0.38PT single crystal is much lower than that of the high dopant content crystal (1.0 mol%) and undoped crystal, which makes it possess excellent pyroelectric performance. By a dynamic method, the measured pyroelectric coefficient and detectivity figure of merit (FD) of 0.2 mol% Fe‐doped PMN–0.38PT single crystal are 439 μC/m2·K and 56.3 μPa−1/2, respectively, both better than those of widely used pyroelectric single crystal LiTaO3. The results imply that the single crystal is a promising candidate for infrared detectors and other pyroelectric applications. The mechanism of doping effect was also discussed based on the principles of crystal chemistry.