ELECTRON MICROSCOPY OF ORTHORHOMBIC PHASE IN MAGNETITE

Abstract
An electron microscopic observation on a synthetic single crystal of magnetite has been carried out at a temperature range between 77°K and room temperature. It was observed that the ordered phases below the low‐temperature transition appear as finely divided stripes. The diffraction patterns in one of the stripes show the extra spots such as (00½), (100), (010), or (11½) in cubic indices. This indicates that the unit cell of the low‐temperature phase should be twice as large as that proposed by Verwey. The ordering scheme proposed should be more complicated than the Verwey order.