Acta Medica Okayama 61 2 2000 Annealing effects on the magnetic and structural properties of single-crystal TDAE-C-60 EN Takashi Kambe Yoshio Nogami Kokichi Oshima <p>Annealing effects on the magnetic and structural properties of single-crystal TDAE-C-60 are investigated. When a crystal is well-annealed at 350 K, ferromagnetic ordering takes place below 16 K, though no magnetic phase transition is shown in as-grown crystal. The saturated magnetization was obtained to be 0.9+/-0.1 mu(B) per C-60. It was first found that the well-annealed crystal shows a structural phase transition around 180 K, probably associated with the orientational ordering of C-60 molecules. On the other hand, the as-grown crystal undergoes no structural phase transition at least down to 30 K while the motion of C-60 molecules is restricted below around 150 K. The possible relation between the low-temperature structure and the magnetic ordering is discussed.</p> No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 329-333 2003 X-ray study of modulated structures of beta-Cu_xV₂O₅ 713 714 EN Nobuaki Nagao Yoshio Nogami Kokichi Oshima Hiroyuki Yamada Yutaka Ueda <p>High resolution X-ray study reveals the wave vector change in the modulated structure of the quasi-one dimensional compound beta'-Cu vanadium bronze. Structural modulation of the reduced wave vector q₀ = (0, 0.305, 0) emerges below 220 K in beta'-Cu_0.29V₂O₅ . For beta'-Cu_0.39V₂O₅, not the single q modulation but two kinds of modulations were observed. A three-fold superlattice structure with q1 = (0, 0.333, 0) appears below 210 K. An incommensurate modulated structure with q2 = (0, 0.26 ? 0.29, 0) coexists below 175 K, whose satellite intensity and b* component Qb have temperature and passing-time dependencies between 140 K and 175 K. The competition between q₁ and q₂ modulations was also observed. It seems that the q₂ is deeply related to the physical property change between 140 K and 180 K confirmed by the decrease in the magnetic susceptibility and the increase in the resistivity.</p> No potential conflict of interest relevant to this article was reported.