Figure 2. Nanoscopic observations of the crystalline domain of the PSC sample.

(a) TEM image of the PSC sample obtained at 1000°C for 1 h. Arrow indicates the crystalline domain boundary. The geometry is the same as that in the microscopic observation (cross-section). (b) SAED pattern of the left-side domain (dark region) and (c) the right-side domain (bright region). The SAED patterns revealed single-crystal features that were identified as fresnoite-type Sr₂TiSi₂O₈ with different crystal zone axes. (d) Near-field TEM image. (e) SAED pattern of the binodal-like nanoparticles with the typical halo pattern, i.e. amorphous phase. (f) EDX spectra of the surrounding region (single-crystal domain, A) and nanoparticle (amorphous, B). At point B, the chemical abundance of Sr was relatively low (indicated by the arrows) compared with the single-domain region.