平成13年度 
物理教室談話会


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.
 
  
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