Dielectric Susceptibility and Strain in Sr1-XBaXTio3 Ferroelectric Thin Films Grown by Pulsed Laser Deposition

Abstract

AbstractThin films of Srl-xBaxTiO3 (SBT) with x = 0 to 0.80 have been grown in situ by pulsed laser deposition onto single crystals of (001) LaAlO3. the films were grown to thicknesses of 0.6 μ.m and found to be single phase, highly oriented, and characterized by x-ray ω scan widths of ≤ 0.5°. the temperature dependence of the dielectric constant and the relative dissipation factor were measured at 1 kHz using au interdigital capacitors deposited on top of the ferroelectric films. the capacitance measurements indicate that the temperature dependence of the dielectric constant of the film is broad and the maximum is shifted relative to the bulk material. the differences between thin film and bulk properties are attributed to strain in the film resulting from film -substrate lattice mismatch. Thick films (∼7 μm) gave direct evidence for strain through cracking and delamination. X-ray diffraction measurements have been made to determine the non-uniform strain in the thin films which was approximately 0.1%.