| 題目 | Structual properties of low-dimensional antiferromagnets |
| 講師 | Dr. Sylvain
Ravy
Laboratoire de physique de solides Universite de Paris-sud |
| 日時 | 11 月 22 日（木）17:30 - 19：00 |
| 場所 | コラボレーションセンター３階 コラボレーション室
（岡山大学津島キャンパス内） |
| 要旨 |
We present x-ray diffraction and diffuse scattering studies on the low dimensional spin-Peierls like systems CuGeO3 and alpha-NaV2O5. On the spin-Peierls system CuGeO3, recent synchrotron radiation studies confirm that very weak one-dimensional (1D) diffuse scattering is still present up to 35 K, i.e. 20 K above the spin-Peierls phase transition. This 1D fluctuations allows one to define a mean-field transition temperature of about 55 K. This result will be discussed with respect to the physical properties of CuGeO3, and in particular with its dynamics. Alpha-NaV2O5 undergoes a complex phase transition in which the charge, the spin and the lattice degrees of freedom are involved. A diffuse scattering study will be presented, together with a anomalous scattering study at the vanadium K edge. This last study shows that the charge ordering occurring below Tc corresponds to a zig-zag ordering on each spin ladder. |
| 世話人 | 理学部物理学科 野上由夫 (TEL:086-251-7770） |
