|Budget Amount *help
¥46,410,000 (Direct Cost: ¥35,700,000、Indirect Cost: ¥10,710,000)
Fiscal Year 2009: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2008: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2007: ¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2006: ¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Intermetallic clathrates have high potential as thermoelectric converters because of the glass-like thermal conductivity in spite of the three dimensional crystal structure. To understand the mechanism of the reduced thermal conductivity, we have studied type-I clathrates encapsulating alkaline-earth and rare-earth atoms by means of structural refinement, thermal, ultrasonic, Raman scattering and photoemission measurements. It is revealed that the guest in a relaxed space inside the cage can rotate among off-center sites and this motion strongly scatters acoustic phonons to reduce the thermal conductivity.