Visualizing local bending of lattice planes by extending two-azimuth synchrotron X-ray diffraction datasets to asymmetric reflection

Synchrotron X-ray rocking curve imaging (RCI) is modified to visualize local bending of lattice planes of a single crystal substrate (XR-V-LBLP). This method uses two-azimuth RCI datasets of asymmetric reflection or symmetric reflection. The analysis algorithm is described and a Python software code is provided in the Supplementary material. The two symmetrically equivalent $$11\bar 24$$ datasets obtained from a GaN (0001) 4-inch wafer are reanalyzed using this software. The normal vector, reciprocal-lattice vector, of the local lattice planes, which is approximately parallel to the sample surface, is formulated as the product of two rotation matrices. This vector is written in polar coordinates using the length and two declination angles, newly introduced in this article. The spatial and probability distributions of the declination angles are also presented. The proposed method enables visualization of the local shape or orientation of the lattice planes of the entire wafer. The limits of application of the method are examined for the samples studied. The sample is found to satisfy two conditions regarding the relative $$d$$-spacing difference and the curvature of the lattice planes at all 50 adjacent μm positions

A Numerical Formula for General Prediction of Interface Bonding between Alumina and Aluminum-Containing Alloys

Interface termination between alumina and aluminum-containing alloys is discussed from a viewpoint of thermodynamics by extending the authors’ previous discussion on the interface termination between alumina and pure metal. A numerical formula to predict interface bonding at alumina-aluminum-containing alloys is proposed. The effectiveness of the formula is examined by extracting information on interface termination from experimental results and first-principle calculations in references. It is revealed that the prediction by the formula agrees quite well with the results reported in the references. According to the formula, a terminating species can be switched from oxygen to aluminum, which had been actually demonstrated experimentally. The formula uses only basic quantities of pure elements and the formation enthalpy of oxides. Therefore it can be applied for most of aluminum-containing alloys in the periodic table and is useful for material screening in developing interfaces with particular functions

Kerr effect microscope combined with a pulse magnet to observe high-entropy alloys fabricated using combinatorial technology

We developed a module-type two-dimensional (2D) polar Kerr effect microscope using a pulse magnet with a pulse width of 13 ms and a maximum magnetic field of 7 kOe to accelerate the development of new soft magnetic materials. We also developed an algorithm and method to extract still images from a measurement movie file when the pulse magnetic field is applied. To evaluate the performance of this instrument, we measured high-entropy alloys based on FeCoMn samples, which were screened and selected using material informatics. Samples obtained through depositing Pt, Zn, Cu, and Ru on high-entropy FeCoMn alloys exhibited a brightness distribution proportional to the Kerr rotation angle in the applied magnetic field. The developed instrument enabled the high-speed magnetic field mapping of composition-spread thin films and is expected to accelerate new material development