We have successfully synthesized new members of layered perovskite oxyhalides with the Ruddlesden-Popper type structure by a high pressure, high temperature method. We found that the halide ions exclusively occupied apical anion sites leading to modifications of coordination environment around the metal centers. Such site preferences of mixed anions provide good opportunities for extending structure and properties of transition metal oxides or halides. Here we present square planar coordination stabilized in Jahn-Teller inactive oxychlorides Sr₂MO₂Cl₂（M＝Mn, Ni, Zn）, a spin ordered/disordered state triggered by anion ordered patterns in Sr₂NiO₃X（X＝F, Cl）, and a novel pressure-induced spin state transition involving a polyhedral transformation in Sr₂CoO₃F.

Designing the next generation of lithium ion batteries （LIBs） requires fundamental information that surprisingly often is still unknown-for example, details of how ions actually move through a working device. Li₇P₃S₁₁ crystal and （Li₂S）x（P₂S₅）_100－x glasses have received a great deal of attention as a solid electrolyte for all-solid-state LIBs because of its extremely high ionic conductivity of 10^－4 to 10^－2 S/cm at room temperature. The authors predict and visualize the conduction pathways of Li ions in Li₇P₃S₁₁ crystal and （Li₂S）x（P₂S₅）_100－x glasses, using reverse Monte Carlo （RMC） modeling and the bond valence sum （BVS） approach with neutron diffraction data. The conduction pathways of Li ions can be classified into two types: relatively “stable” regions and “metastable” regions for Li ions. Furthermore, the authors use quasielastic neutron scattering to directly monitor the fast diffusion of Li ions in Li₇P₃S₁₁ crystal. According to the jump diffusion model, Li ions migrate between stable regions within a jump length ＜l＞＝4.3 Å along conduction pathways.

We have applied inelastic X-ray scattering （IXS） technique to observing phonon spectra in rare-earth compounds. IXS technique has an advantage to inelastic neutron scattering to avoid seeing magnetic excitations, which are often observed in the low energy spectra of rare-earth compounds. In this review, we mentioned IXS results of filled skutterudite compounds. In a series of ROs₄Sb₁₂, we have discussed electron phonon coupling in low-lying optical modes, which is connected with heavy fermion behavior in these compounds. In an alloy system of Pr（Os_1－xRu_x）₄Sb₁₂, we have discussed anharmonic potential at the rare-earth site which may be affect by nature of superconductivity and/or heavy fermion behavior.

The atomic structures of liquid-phase bonded heterointerfaces between Al alloy and AlN single crystal was examined using aberration-corrected scanning transmission electron microscopy combined with high-sensitive energy-dispersive X-ray microanalysis. The formation of O-Mg-O monolayer structure was found at the interface, facilitating the bonding between the two dissimilar crystals during liquid-phase bonding processes. Understanding the spontaneous formation of such layered transition structures at the heterointerfaces will be a key for fabricating very stable liquid bonded Al alloy / AlN heterointerfaces.