High-Temperature Magnetism as a Probe for Structural and Compositional Uniformity in Ligand-Capped Magnetite Nanoparticles.

ABSTRACT: To investigate magnetostructural relationships in colloidal magnetite (Fe₃O₄) nanoparticles (NPs) at high temperature (300-900 K), we measured the temperature dependence of magnetization (M) of oleate-capped magnetite NPs ca. 20 nm in size. Magnetometry revealed an unusual irreversible high-temperature dependence of M for these NPs, with dip and loop features observed during heating-cooling cycles. Detailed characterizations of as-synthesized and annealed Fe₃O₄ NPs as well as reference ligand-free Fe₃O₄ NPs indicate that both types of features in M(T) are related to thermal decomposition of the capping ligands. The ligand decomposition upon the initial heating induces a reduction of Fe³⁺

SUBMITTER: Kolen'ko YV 

PROVIDER: S-EPMC4259497 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature