Single-crystalline hematite rhombohedra and magnetic nanocomposites of iron and magnetite and methods of making same
AssigneeThe Research Foundation of State University of New York
InventorsStanislaus S. Wong, Tae-Jin Park
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Abstract
The present invention relates to nanostructures, in particular to hematite rhombohedra and iron/magnetite nanocomposites, and methods of making same.
Claims20
A single-crystalline hematite rhombohedron wherein the rhombohedron is at least about 90% free of defects and/or dislocations.
A method of making single-crystalline hematite rhombohedra, the method comprising:
- (a) mixing Fe2O3 nanopowder and a salt to form a precursor mixture, wherein the ratio of the Fe2O3 nanopowder to the salt is about 0.5:40 to about 10:40;
- and
- (b) heating said precursor mixture at about 500 to about 1000° C. to provide single-crystalline hematite rhombohedra,
- wherein the rhombohedra have an average aspect ratio of about 0.5 to about 2.
A method of making single-crystalline hematite rhombohedra, the method comprising:
- (a) mixing Fe2O3 nanopowder and a salt to form a precursor mixture;
- (b) adding surfactant to the precursor mixture;
- and
- (c) heating said precursor mixture at about 500 to about 1000° C. to provide single-crystalline hematite rhombohedra,
- wherein as the relative amount of the Fe2O3 nanopowder to surfactant increases, the average aspect ratio of the rhombohedra increases nonlinearly.
A crystalline rhombohedral nanocomposite of Fe and Fe3O4.
A method of making substantially monodisperse nanocrystalline rhombohedral composites of Fe and Fe3O4, the method comprising:
- (a) providing a hematite precursor;
- and
- (b) heating the hematite precursor at about 200 to about 500° C. in the presence of a reductive gas to make nanocrystalline composites of Fe and Fe3O4.
Dependencies are inferred from the claim text.