Shape-controlled crystal growth of Sr3NbGa3Si2O14 and Sr3TaGa3Si2O14 piezoelectric single crystal by micro-pulling-down method
We have grown the shape-controlled Sr<inf>3</inf>NbGa<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> (SNGS) and Sr<inf>3</inf>TaGa<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> (STGS) langasite-type crystals by the μ-PD method. Columnar-shaped SNGS and STGS crystals were grown using the Pt-Rh crucible with a columnar die in 3 mm diameter. Grown crystals indicated high transparency and approximately 3 mm diameter. Chemical phases of grown crystals were identified as a single phase of langasite-type structure. The lattice parameters of grown crystals were almost consistent with those of crystals grown by Czochralski (Cz) method. In the X-ray rocking curve measurements, the grown crystals indicated equivalent crystallinity to the crystal grown by Cz method.
Ca3Ga2Ge4O14 (CGG)-type Sr3Nb0.95Ga3.083Si2O14 single crystal grown by the Czochralski method for piezoelectric applications
Abstract The stoichiometric composition (Sr 3 NbGa 3 Si 2 O 14 ) was found to melt incongruently. Hence, the composition of the starting melt for Czochralski growth was chosen from the differential thermal analysis (DTA) results. We found that Sr 3 Nb 0.95 Ga 3.083 Si 2 O 14 (SNGS) was the proper composition to grow. This resulted in SNGS single crystals having a Ca 3 Ga 2 Ge 4 O 14 (CGG) structure (point group 32, space group P321), grown by the conventional Czochralski method.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.