Iron nanoparticles in amorphous BaTiO3 thin films with large third-order optical nonlinearity

Abstract

Composite thin films comprising nanometer-size iron particles embedded in an amorphous BaTiO3 matrix (Fe/BTO) were fabricated by alternate pulsed-laser deposition from pure metallic Fe and ceramic BaTiO3 targets. The distribution of Fe nanoparticles in BTO matrix was observed using high-resolution transmission electron microscope. X-ray photoelectron spectroscopy was used to check the Fe chemical bond state for the deposited films. Optical absorption spectra showed no significant surface plasma resonance peak in the wavelength range of 330–800 nm. The nonlinear optical properties of the Fe/BTO films were determined using the Z-scan method at the wavelength of 532 nm with laser duration of 10 ns. The real and imaginary parts of the third-order nonlinear susceptibility χ(3) were determined to be 7.18×10−7 esu and −8.60×10−8 esu, respectively. The results show that Fe/BTO composite thin films have great potential in designing nonlinear optical devices.