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Synthesis of Photoactive Magnetic Nanoparticles with Atomic Layer Deposition



Yun Zhou, David M. King, Jianhua Li, Kathryn S. Barrett, Ronald B. Goldfarb, Alan W. Weimer


Iron-based magnetic nanoparticles have been produced by decomposition of iron oxalate powder. The micron-sized iron oxalate powder was first ground using a cryogenic milling process. A titanium dioxide (TiO2) thin film was then deposited on the synthesized iron nanoparticles using an in-situ atomic layer deposition (ALD) process at 100 °C with TiCl4 and H2O2 as precursors. However, due to the high surface area, the iron nanoparticles were unstable and spontaneously oxidized when exposed to H2O2 during the TiO2 ALD process, thus reducing the magnetic moment of the core particles. As an improvement in the process, prior to the TiO2 deposition, an aluminum nitride (AlN) film was deposited in-situ to coat and passivate the iron core particles. The AlN ALD was performed at 250 °C using trimethylaluminium (TMA) and ammonia (NH3) as precursors. This passivation provided for a significant decrease in the iron oxidation as determined by X-ray diffraction and magnetization measurements. Photoactivity of the TiO2 film was demonstrated by decomposing methylene blue solution under ultraviolet irradiation.
Industrial and Engineering Chemistry Research


Iron nanoparticles, atomic layer deposition, titanium dioxide, aluminum nitride, passivation, photocatalyst


Zhou, Y. , King, D. , Li, J. , Barrett, K. , Goldfarb, R. and Weimer, A. (2010), Synthesis of Photoactive Magnetic Nanoparticles with Atomic Layer Deposition, Industrial and Engineering Chemistry Research, [online], (Accessed March 4, 2024)
Created March 7, 2010, Updated October 12, 2021