Annealing study of Fe 2O 3 nanoparticles: Magnetic size effects and phase transformations

X. N. Xu; Y. Wolfus; A. Shaulov; Y. Yeshurun; I. Felner; I. Nowik; Yu Koltypin; A. Gedanken

doi:10.1063/1.1457544

Annealing study of Fe ₂O ₃ nanoparticles: Magnetic size effects and phase transformations

X. N. Xu^*
, Y. Wolfus
, A. Shaulov
, Y. Yeshurun
, I. Felner
, I. Nowik
, Yu Koltypin
, A. Gedanken

^*Corresponding author for this work

Racah Institute of Physics

Research output: Contribution to journal › Article › peer-review

86 Scopus citations

Abstract

Sonochemically synthesized Fe ₂O ₃ nanoparticles were annealed in air or in vacuum while their magnetization was continuously recorded. Annealing in vacuum at temperatures T _a between 240 and 450°C produced nanophases of γ-Fe ₂O ₃ with average particle size ranging from 4 to 14 nm, depending on T _a. Phase transformation into α-Fe ₂O ₃ occurred directly by annealing in air, or via an intermediate Fe ₃O ₄ phase by annealing in vacuum at temperatures higher than 450°C. Mapping the correlation between the magnetic properties and the annealing conditions, enables control of the annealing process to obtain nanocrystals of γ-Fe ₂O ₃, α-Fe ₂O ₃, or Fe ₃O ₄ with different particle size and magnetic properties.

Original language	English
Pages (from-to)	4611-4616
Number of pages	6
Journal	Journal of Applied Physics
Volume	91
Issue number	7
DOIs	https://doi.org/10.1063/1.1457544
State	Published - 1 Apr 2002

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abstract = "Sonochemically synthesized Fe 2O 3 nanoparticles were annealed in air or in vacuum while their magnetization was continuously recorded. Annealing in vacuum at temperatures T a between 240 and 450°C produced nanophases of γ-Fe 2O 3 with average particle size ranging from 4 to 14 nm, depending on T a. Phase transformation into α-Fe 2O 3 occurred directly by annealing in air, or via an intermediate Fe 3O 4 phase by annealing in vacuum at temperatures higher than 450°C. Mapping the correlation between the magnetic properties and the annealing conditions, enables control of the annealing process to obtain nanocrystals of γ-Fe 2O 3, α-Fe 2O 3, or Fe 3O 4 with different particle size and magnetic properties.",

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AU - Xu, X. N.

AU - Wolfus, Y.

AU - Shaulov, A.

AU - Yeshurun, Y.

AU - Felner, I.

AU - Nowik, I.

AU - Koltypin, Yu

AU - Gedanken, A.

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N2 - Sonochemically synthesized Fe 2O 3 nanoparticles were annealed in air or in vacuum while their magnetization was continuously recorded. Annealing in vacuum at temperatures T a between 240 and 450°C produced nanophases of γ-Fe 2O 3 with average particle size ranging from 4 to 14 nm, depending on T a. Phase transformation into α-Fe 2O 3 occurred directly by annealing in air, or via an intermediate Fe 3O 4 phase by annealing in vacuum at temperatures higher than 450°C. Mapping the correlation between the magnetic properties and the annealing conditions, enables control of the annealing process to obtain nanocrystals of γ-Fe 2O 3, α-Fe 2O 3, or Fe 3O 4 with different particle size and magnetic properties.

AB - Sonochemically synthesized Fe 2O 3 nanoparticles were annealed in air or in vacuum while their magnetization was continuously recorded. Annealing in vacuum at temperatures T a between 240 and 450°C produced nanophases of γ-Fe 2O 3 with average particle size ranging from 4 to 14 nm, depending on T a. Phase transformation into α-Fe 2O 3 occurred directly by annealing in air, or via an intermediate Fe 3O 4 phase by annealing in vacuum at temperatures higher than 450°C. Mapping the correlation between the magnetic properties and the annealing conditions, enables control of the annealing process to obtain nanocrystals of γ-Fe 2O 3, α-Fe 2O 3, or Fe 3O 4 with different particle size and magnetic properties.

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Annealing study of Fe ₂O ₃ nanoparticles: Magnetic size effects and phase transformations

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