Nagoya Institute of Technology / Ceramics Research Laboratory / 機能創製研究部門 /
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In the nature world, there are lost of materials with marvelous active properties. Woods have porous materials with super fine structure, which structure is diffiult to realize in the sysnthesis of ceramics materials at the present human technology. In hte nature, however, wood ceramics already exists, which is a kind of fossil wood made by nature for huge time. In our group, we try to synthesize new type porous ceramis materials by imitating fossil wood. Fig.1 shows a SEM micrograph of TiO2 wood synthesized by sol-gel reactrion, where the wood is used as mother material.
Fig. 1 SEM micrograph of TiO2 wood
Positive temperature coefficient of resistivity (PTC) thermisters, such as BaTiO3or varistors such as ZnO shows drastic change of electric resistivity at a ceartain temperature or a voltage. The materials which control their own physical properties depending on the circumstanses are called "intelligent materials". We study about the composite materials showing intelligent chracterisities. For example, the materials containing ZnO and carbon rubber composite apperas the PTC effect depending on the voltage. Our goal is the synthesis of the the tunable PTC thermsiters controlled by the applied voltage.
Fig. 2 BaTiO3 Composite material
By utilizing magneto_optical effect, magnetic field can be visualized. Such device called as "MO indicator" is prepared by liquid phase epitaxi (LPE) technique in our laboratory. The figure 3 shows an example of the visualization of the magnetic flux penetrating in the high Tc superconductor YBCO film. With applying magnetic filed to the YBCO film, the dendrite penetration of the magnetic flux occurs in the YBCO film.
Fig.3 Observation of the penetrated magnetic flux in the ＹＢＣＯ film
For the appliation of MEMS devices such as the micro-magnetic motor, actuator etc., the NdFeB thin film magnets are synthesized by RF suputtering and post annealing technique. Figure 4 show the high performance of the magnetic properties of the film and microstructures of the film.
Fig. 4 The TEM micrograpgh of the cross section and the magnetic hysteresis loop of the NdFeB thin film magnet.