Composition dependence of crystal structure and electrical properties for epitaxial films of Bi(Zn1/2Ti1/2)O3-BiFeO3 solid solution system

Epitaxial xBi(Zn1/2Ti1/2)O-3-(1-x)BiFeO3 films were grown on (100)(c)SrRuO3//(100)SrTiO3 substrates by metal organic chemical vapor deposition (MOCVD). The effects of x value on the crystal structure and the electrical properties were investigated. Constituent phase changed from rhombohedral symmetry to two types of tetragonal ones with different unit cell volume and tetragonality. Rhombohedral phase and the tetragonal phase with smaller tetragonality were not ascertained to transform to cubic phase up to 800 degrees C from high temperature XRD results. Relative dielectric constant measured at room temperature showed the maximum value at x = 0.21 near the phase boundary between tetragonal and rhombohedral symmetries. Leakage current became small when the measurement temperature decreased at 80 K and the ferroelectricity monotonously decreased with increasing x values and was not ascertained above 0.26. (C) 2010 The Ceramic Society of Japan. All rights reserved.