| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2006: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Research Abstract |
By use of synchrotron radiation, powder x-ray diffraction of LnBi (Ln = La, Nd, Sm, Gd, Tb, Ho and Tm) with a NaCl-type structure has been studied up to 35 GPa at room temperature. The detailed pressure-volume relationship for SmBi is obtained. The isostructural phase transition reported by Benedict et al. is not found at around 2.6 GPa. However, we have observed a first-order phase transition for SmBi at around 18 GPa. SmBi transforms from the NaCI-type to a tetragonal (distorted CsCl-type) structure with the volume collapse of about 8.2 % at around 18 GPa. Crystal data of the high-pressure phase of SmBi are a = 3.775(5) Å, c = 3.25 (2) Å, c/a = 0.86 and V = 46.4 (3) Å^3 at 20.3 GPa. The structure of SmBi at high pressure is isostructural with that of SmAs. A bulk modulus of SmBi is obtained from the volume vs. pressure curve fitted by a Birch equation of state. The bulk modulus and its pressure derivative of this compound are B_0 = 67 ± 2 GPa, B_0' = 2.6 ± 0.3. We have found also the structural phase transitions for LnBi (Ln = La, Nd, Sm, Gd, Tb, Ho and Tm) at high pressures.
|
