In this article, we review the two subjects; what kind of new superconductors we have discovered and what kind of new superconductors we want to discover. In particular, we review our present status how to find higher-Tc superconductors along the following lines. 1) 2-dimensional Cu-oxides having different crystal structures with CuO2 planes, such as ladders, Lieb model Cu-oxide ...etc. 2) Metal superconductors including light elements (boron, carbon...etc.), being suggested with MgB2, diamond...etc. Recently, we found a series of new superconductors “B (boron) /Al doped SiC” which belongs to the same category with boron doped diamond and Si...etc. 3) Finally, we discuss the third way-the way of serendipity.
Neutron powder diffraction is a powerful technique to clarify the relationship between the crystal structures and the properties of functional materials. The improvements in both intensity and resolution of powder diffractometers make it possible to optimize materials function in a materials development process as well as to discover new structural properties. In this article, development of pulsed neutron diffractometers carried out at KENS and J-PARC is reviewed. The article includes 1) two powder diffractometers Vega and Sirius at KENS which adopted arrays of hundreds of position sensitive detectors and a long-flight path supermirror guide for the first time, and 2) development of J-PARC powder diffractometers.
This paper shows a technique to acquire a tilt series of dark-field transmission electron microscopy (DFTEM) images for superlattice domains formed in ordering alloys. Fundamental points are as follows 1) use of a superlattice reflection with a relatively long extinction distance (small structure factor) to satisfy the projection requirement and 2) careful realignment of the electron beam to keep the diffraction condition during tilting the specimen. Tomographic reconstruction from the obtained DFTEM tilt series visualizes three-dimensional morphology and distribution of the superlattice domains, demonstrating the feasibility of the DFTEM tomography.