Growth and electrical properties of Pb(Sc 1/2Nb 1/2)O 3–Pb(Mg 1/3Nb 2/3)O 3–PbTiO 3 ternary single crystals by a modified Bridgman technique

Abstract

Single crystals of 0.05Pb(Sc 1/2Nb 1/2)O 3–0.63Pb(Mg 1/3Nb 2/3)O 3–0.32PbTiO 3 have been grown directly from melt by a modified Bridgman technique. The crystals with perovskite structure were 15 mm in diameter and 20 mm in length. The segregation during the growth of the single crystals was studied by means of X-ray diffraction analysis. The results show that PbTiO 3 content increases throughout the crystal growth. The electrical properties of the single crystals oriented along the [0 0 1] axis have been characterized. The plates cut from the seed end of a boule exhibited a permittivity ( ε 33 ε 0 ) of about 3500, dielectric loss tangent (tg δ)<1%, dielectric constant peaks at 162°C, piezoelectric constant ( d 33)≈1200 pC/N, and electromechanical coupling factor ( k t)≈60% for the thickness mode. Our results show that xPb(Sc 1/2Nb 1/2)O 3– yPb(Mg 1/3Nb 2/3)O 3–(1- x- y)PbTiO 3 single crystals are promising for a wide range of electromechanical transducer applications.