Preparation and Dielectric Properties of High Tc Relaxor-Based Single Crystals

Single crystals of the xPB(Sc 1/2 Nb 1/2 )O 3 -yPb(Zn 1/3 Nb 2/3 )O 3 -zPbTiO 3 (PSZNT) and xPb(In 1/2 Nb 1/2 )O 3 -yPb(Zn 1/3 Nb 2/3 )O 3 -zPbTiO 3 (PIZNT) ternary systems have been synthesized by a flux method using PbO flux. The single crystals were grown in a Pt crucible by a mass crystallization, achieved by slow cooling of the 55PbO@45PSZNT or PIZNT molten solution with 1.5-3°C/h from 1,230-1,250°C to 850°C. The resulting crystals are 2-5 mm in length and dark brown perovskite. For the PSZNT10/75/15(mol%) system, the (001) single crystal near the morphotropic phase boundary, showed a room temperature dielectric constant after poling of 2,700 and a very low dielectric loss of 0.5%. A maximum dielectric constant leached to 22,000 at 216°C. On the other hand, the PIZNT10/77/13(mol%) system showed Tc=222°C, l r =3,900 at 20°C and l r =14,000 at Tc.