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斉藤 淳一; 武末 尚久*; 木場 知将*; 工藤 淳貴*; 松尾 直樹*
no journal, ,
In general, piezoelectrics show their highest performance if they are single crystals. However, many of the growth procedures are time-consuming and unpractical, which results in our choice of the sintered polycrystal ceramics for practical use. This general situation causes trade-off between the performance and the effort of process, which motivated us to develop a simple process to obtain the highly-oriented dense integration of piezoelectric single-crystal nanoparticles. Intuitibely saying, the expected process can be realized by using cube- or rectangular-shaped particles, because their plane-to-plane contacts allow their crystallographically oriented ordering to include quite a little space among them. Such the particle is called nanocube, and there have been found the several kinds so far. For this work, the most adequate nanocube is of barium titanate (BT); therefore, we decided to choose BT nanocubes as the model system and exploit a shape of real dices as imitations of the nanocubes for a first trial experiment of this work. In this experiment, dices are mechanically agitated or pressed in soft mediums such as polyvinyl alcohol, and continuous monitoring of the dices are done during the mechanical operations. The results will be presented in the meeting.
斉藤 淳一; 木場 知将*; 工藤 淳貴*; 松尾 直樹*; 武末 尚久*
no journal, ,
We fabricated nanocube crystals of barium titanate by hydrothermal synthesis and also solvothermal, according to the methods of prior studies. Each particle is the single crystal and has the well-known conventional crystal structure, which was confirmed by TEM and X-ray diffraction. Currently, we are trying to build the oriented dense assemblage by mechanical operations such as stirring the particles in a small container, based on the previous imitation experiment with real dices stirred in a cylinder. How our praticles are crystallographically oriented and ordered were confirmed by X-ray diffraction in various conditions of the operations. The result will be presented in the meeting.
斉藤 淳一; 工藤 淳貴*; 木場 知将*; 松尾 直樹*; 武末 尚久*
no journal, ,
We synthesized single-crystal nancubes of barium titanate (BT), known as a typical perovskite ferroelectrics, by hydrothermal synthesis and also solvothermal. Typical forms of the nanocubes are given. The next stage of this fabrication includes integration and solid-solutionaizing BT nanocubes with other similar substances; the former is expected to provide large spontaneous electric polarization of the single-crystal level, and the latter gigantic piezoelectric response, called morphotropic phase boundary effect; we have already been working on the former, so we subsequently decided to work on the latter. In this work, we try the same synthesis methods involving zirconia or zirconium complex for a zirconium substitute to titanium. The obtained substance will be investigated by TEM, X-ray diffraction, and dielectric measurements. The result will be presented in the meeting.
斉藤 淳一; 松尾 直樹*; 木場 知将*; 工藤 淳貴*; 武末 尚久*
no journal, ,
We synthesized single-crystal nancubes of barium titanate (BT), known as a typical perovskite ferroelectrics, by hydrothermal synthesis and also solvothermal; our pressed and sintered sample shows typical temperature dependence of capacitance of BT. The next stage of this fabrication includes crystallographically highly oriented dense integration and solid-solutionaizing BT nanocubes with other similar substances; the former is expected to provide large spontaneous electric polarization of the single-crystal level, and the latter gigantic piezoelectric response, called morphotropic phase boundary effect. We have already been working on the former by mechanical agitation, e.g. stirring the nanocubes in a small container; we obtained typical data of X-ray diffraction of BT and found a tendency for our nanocubes to be oriented therefore, we subsequently decided to work on the latter. In this work, we try the same synthesis methods involving zirconia or zirconium complex for a zirconium substitute to titanium and also calcium hydroxide for calcium to barium. Conventionally sintered polycrystal samples of this system are known to show high performances as piezoelectrics, so it is possible that our integrations show the higher performance than the conventional samples. The obtained substance will be investigated by TEM, X-ray diffraction, and dielectric measurements. The result will be presented in the meeting.