New water-based sol–gel synthesis routes for LaNi0.6Fe0.4O3-δ thin films

Abstract

Two synthesis routes for approximately 100nm thick layers of LaNi0.6Fe0.4O3-δ (LNF64) are presented. Aqueous solutions of acetate or nitrate-precursors were deposited on Ce0.9Gd0.1O2-δ substrates by spin coating. After thermal annealing at 700°C for 3h, the thin films were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The DC electrical conductivity of the LNF64 thin films was determined by four-point van der Pauw measurements as a function of temperature (20≤T/°C≤400) at 1×10−3≤pO2/bar≤1. At the surface and cross section a nanocrystalline microstructure with grain sizes of approximately 50–100nm was observed. The DC electrical conductivity of the thin films increases with increasing temperature and increasing pO2. A maximum electrical conductivity of 320S/cm was found at 400°C and pO2=1bar which agrees with the literature data for LNF64 bulk samples.