Short-range ordering and {1,1/2,0} diffuse intensity maxima in ZrN x

Abstract

Diffuse intensity maxima in ZrN x caused by short-range ordering (SRO) of nitrogen atoms or vacancies are shown in electron diffraction patterns along four different low-index zone-axes. Analysis of the shape of the diffuse intensity was performed using an equation developed by Sauvage and Parthé [1]. Additional {1,1/2,0} diffuse intensity maxima were also observed and these have not been previously reported for interstitial carbides and nitrides with a NaCl-type crystal structure. Both a Kohn construction, which assumes that the positions of 2 k F110 yield the diffuse intensity maxima, and microdomain crystal models based on M 2X or M 4X 3 crystal structures, are presented as possible explanations for the origin of the {1,1/2,0} diffuse intensity maxima. The close relationship between the SRO model and the shape of the Fermi surface indicates that the Fermi surface in ZrN has nearly the same shape as that of TiN.