Epitaxial growth and dielectric properties of homologous Srm−3Bi4TimO3m+3Srm−3Bi4TimO3m+3 (m = 3,4,5,6)(m=3,4,5,6) thin films

Abstract

The first four members of Bi-layered Srm−3Bi4TimO3m+3Srm−3Bi4TimO3m+3 homologous series with m = 3,m=3, 4, 5, and 6, i.e., Bi4Ti3O12,Bi4Ti3O12, SrBi4Ti4O15,SrBi4Ti4O15, Sr2Bi4Ti5O18,Sr2Bi4Ti5O18, and Sr3Bi4Ti6O21,Sr3Bi4Ti6O21, were grown on SrTiO3SrTiO3 (001) single-crystal substrates by pulsed-laser deposition. X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) reveal that the films grew epitaxially with in-plane epitaxial alignment of [10]Srm−3Bi4TimO3m+3‖[010]SrTiO3.[11̄0]Srm−3Bi4TimO3m+3‖[010]SrTiO3. HRTEM cross-sectional images show that the films with m = 3,m=3, 4, and 5 are nearly free of intergrowth, whereas a number of growth defects were observed in the film with m = 6.m=6. Using an evanescent microwave probe, the room-temperature dielectric constants of these epitaxial films are measured to be 221±13,221±13, 205±15,205±15, 261±29,261±29, and 249±17249±17 for films with m = 3,m=3, 4, 5, and 6, respectively. © 2002 American Institute of Physics.