Synchrotron X-ray Absorption Spectra of Iron Oxides Synthesized by Co-precipitation at Varying Temperatures.

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 (25OC, 60OC) 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. [ABSTRACT FROM AUTHOR]