| Budget Amount *help |
¥52,000,000 (Direct Cost: ¥40,000,000、Indirect Cost: ¥12,000,000)
Fiscal Year 2004: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2003: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2002: ¥34,450,000 (Direct Cost: ¥26,500,000、Indirect Cost: ¥7,950,000)
Fiscal Year 2001: ¥13,520,000 (Direct Cost: ¥10,400,000、Indirect Cost: ¥3,120,000)
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| Research Abstract |
Materials consisting of IV^<th> group elements (C, Si and Ge) showing exotic electronic properties have been prepared and their physical properties have been studied from the view point of the fundamental aspects. A new magnetic nano cluster solid showing polyhedral networks and containing Mn atoms as a d-transition metal system are prepared. This compounds shows a ferro magnetic transition at 6 K and a spin glass behavior when it approaches to further low temperature. These properties can be interpreted in terms of the interaction of the conduction electrons spreading over the nano cluster network and the d-electrons relatively localized on the Mn atoms. In our experiments, silicon polyhedral networks containing Ce was proposed to be synthesized and show a ferromagnetic phase transition in the beginning, but this has been found to be a mistake in the determination of the crystal structure. However, afterward it has been reported that Ge nano polyhedral networks can accommodate Eu inside the cage structure and this shows a ferro magnetic phase transition. Consequently, nano polyhedral network system containing the both d-transition and f-transition elements are now present. When Ba atoms are accommodated in side the cage, silicon polyhedral type I system shows superconductivity. The mechanism of the superconductivity has been elucidated for Si type I clathrates consisting of pure ^<28>Si and ^<30>Si elements. It has been concluded on the basis of this isotope and specific heat capacity studies that the mechanism of the superconductivity in this system is BCS mediated mainly by infra cluster phonons.
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