Strain-induced phase-structure of Fe2O3 nanoparticles

Abstract

Selective synthesis of Fe2O3 nanomaterials with desired phase-structure is of great importance for broadening and improving their industrial applications. In this paper, the structure-phase transformation in the as-prepared samples with different annealing process is studied, trying to find a facile route to fabricate α- and γ-Fe2O3 nanoparticles by inducing external strain in a well control mode, which is of great importance for the design and applications of the iron oxide. The high-resolution transmission electron microscope, X-ray photoelectron spectra and Raman spectra analysis clearly demonstrate that the long-term thermal annealing and rapid thermal annealing can result in the formation of α- and γ-Fe2O3 confined in Al2O3 matrix, respectively. The magnetic properties display that the residual magnetization and coercive force values for the γ-Fe2O3 nanoparticles are much higher than those for the α-Fe2O3 nanoparticles, which supplies an enhanced magnetic route by selective synthesis of confined Fe2O3 nanoparticles with desired strain-induced phase-structure and paves the ways for the applications of Fe2O3 nanoparticles in magnetic nano-devices.