Local structure analysis of DyN-ZrN solid solutions

We performed various synchrotron X-ray measurements to extract local and average structures of DyN-ZrN solid solutions. ZrN and AlN have typical phase separation systems, undergoing chemical segregation into ZrN-rich and AlN-rich domains. However, the phase separation of DyN-ZrN has not been investigated. We performed the nanoscale structural analysis to clarify the phase separation in DyN-ZrN by combining X-ray absorption fine structure and high-energy X-ray diffraction. Consequently, discontinuities indicating phase separation were observed in the average and local structures. The results showed that it is differs from the conventional phase separation mechanism caused by the difference in the crystal structure. The DyN-ZrN solid solution has a rock-salt type cubic crystal structure, and there are instabilities such as the chemical order of the metal site and the distribution of the bond length of the nitrogen site. A phase separation has occurred to reduce these structural instabilities.