Structural and dielectric properties of Ga-modified BiFeO3-PbTiO3 crystalline solutions

The dielectric and structural properties of Bi(GaxFe1-x)O-3-PbTiO3 (BGF-PT) crystalline solutions have been investigated. Studies have focused on phase-pure perovskite materials. With increasing Ga content, we have found: (i) a coexistence of tetragonal and rhombohedral ferroelectric phases; (ii) a multicell perovskite structure for BGF-0.3PT; and (iii) a maximum tetragonal c/a ratio for the composition BGF-0.6PT with x=0.25. Also, Ga modification increases the electrical resistivity to greater than or equal to10(12) Omega cm, reduces the dielectric loss or tan delta over a wide temperature range, and increases the dielectric constant K. We have developed BGF-PT materials with values of K>400 and of tan delta<0.03. (C) 2003 American Institute of Physics.