Nanostructure of Mg85Y9Zn6 ternary alloy ingot with long-period stacking order structure has been examined by synchrotron radiation small-angle X-ray scattering. The scattering patterns showed sharp reflections corresponding to large domains of 10H, 18R and 14H structures, with in-plane ordering. After annealing at 673 K, the peak intensity of 18R increased, and the diffraction peak corresponding to in-plane ordering sharpened. The domain size of in-plane ordering was much smaller than the domain thickness of 18R in the stacking direction.

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Break junctions of some HCP metals are known to yield single-atom contacts (SACs) frequently at 4 K but rarely at room temperature (RT). In this work, we show that SACs of Cd and Ti can be produced at RT not by opening their junctions but by closing them. For both Cd and Ti, the conductance histogram measured at junction closing reveals a clear SAC peak whereas the SAC peak appears marginal in the histogram obtained at junction opening. Because SACs are formed through necking deformations in the junction opening, while not in the junction closing, our observations suggest that the rare SAC formation reported for some HCP break junctions at RT would be due to necking deformations. The observed histograms also determine the hitherto unknown SAC conductance of Cd and Ti as 0.7G0 and 0.8G0, respectively.

Development of LPSO structure and in-plane ordering during annealing the Mg85Y9Zn ternary alloy sample at 673 K (400°C) was examined by synchrotron radiation small-angle scattering/ diffraction measurements. By examining the first diffraction peaks for 18R, 10H, and in-plane order spot, the growth kinetics of in-plane order domain and the transition from 10H into 18R were discussed. The domain growth of in-plane order was characterized by small domain with little correlation between neighboring segregation layers.

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