X-RAY-DIFFRACTION, IR SPECTROMETRY AND HIGH-RESOLUTION ELECTRON-MICROSCOPY ON ORDERED ZINC-SUBSTITUTED MAGHEMITES

Well-crystallised particles with controlled morphology of zinc-substituted maghemite prepared by oxidation at 445-degrees-C for 9 h from zinc-substituted magnetite have been investigated by a combination of X-ray diffractions, IR spectrometry and high resolution electron microscopy. A pronounced development of cation vacancy ordering on octahedral sites with a period of 1/3 unit cell vector along the [100] and [110] directions has been observed. The presence of twins of the [100] type have also been detected.