Diffraction from a Natural Grain Boundary in a Magnetite Bicrystal

The structure of a natural small‐angle boundary in a magnetite bicrystal was investigated by X‐ray diffraction. This boundary was a “general” type with a mixed twist and tilt character. The grain‐boundary reflections observed around an 040 matrix reflection were in good agreement with those predicted by Boll‐mann's O‐lattice theory. These extra reflections appear to arise from a predominantly planar dislocation network. The structural width of the boundary, determined from the length of the relrods of the grain‐boundary reflections, was of the order of four unit cells, close to the average spacing of the expected dislocation network.