Abstract

Witoon Tangwatanakul^1,2 and Chitnarong Sirisathitkul*^3,4

DOI : http://dx.doi.org/10.13005/ojc/35Specialissue105

Synchrotron X-ray absorption near edge spectroscopy (XANES) and extended X-ray fine structure (EXAFS) are used to study the effect of temperature in the co-precipitation synthesis of iron oxides. Nanoparticles are rod-like and agglomerate into microscale aggregates. XANES spectra complement X-ray diffractometry in the phase identification of inverse spinel structured maghemite (γ-Fe₂O₃). In addition to the smallest crystallite size, EXAFS analysis revealed the highly distorted structure in the sample synthesized at 90°C. The samples synthesized at lower temperatures (25°C, 60°C) are ferrimagnetic with much larger magnetizations. The variation in magnetic properties with the synthetic temperature is related to the differences in crystallite size and distortion in the structure of γ-Fe₂O₃ nanoparticles.

Co-Precipitation; EXAFS Spectroscopy; Maghemite; Synchrotron X-Ray Absorption; XANES Spectroscopy

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