Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen

TitleThermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen
Publication TypeJournal Article
Year of Publication2017
AuthorsUnni, M., A. M. Uhl, S. Savliwala, B. H. Savitzky, R. Dhavalikar, N. Garraud, D. P. Arnold, L. F. Kourkoutis, J. S. Andrew, and C. Rinaldi
JournalACS Nano
Volume11
Issue2
Pagination2284 - 2303
Date PublishedApr-02-2019
ISSN1936-0851
Abstract

Decades of research focused on size and shape control of iron oxide nanoparticles have led to methods of synthesis that afford excellent control over physical size and shape but comparatively poor control over magnetic properties. Popular synthesis methods based on thermal decomposition of organometallic precursors in the absence of oxygen have yielded particles with mixed iron oxide phases, crystal defects, and poorer than expected magnetic properties, including the existence of a thick “magnetically dead layer” experimentally evidenced by a magnetic diameter significantly smaller than the physical diameter. Here, we show how single-crystalline iron oxide nanoparticles with few defects and similar physical and magetic diameter distributions can be obtained by introducing molecular oxygen as one of the reactive species in the thermal decomposition synthesis. This is achieved without the need for any postsynthesis oxidation or thermal annealing. These results address a significant challenge in the synthesis of nanoparticles with predictable magnetic properties and could lead to advances in applications of magnetic nanoparticles.

URLhttp://pubs.acs.org/doi/10.1021/acsnano.7b00609
DOI10.1021/acsnano.7b00609
Short TitleACS Nano