Affiliations: Neutron Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan | ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK | Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai 319-1195, Japan | Department of Physics, Okayama University, Okayama 700-8530, Japan | Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan | Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai 319-1106, Japan
Abstract: The static spin structure factor S(Q) of CuGeO3 was determined above its spin-Peierls transition temperature by inelastic neutron scattering. At 20 K, S(Q) has a Lorentzian line shape centered at the antiferromagnetic (AF) zone center. With increasing temperature, however, it splits into two peaks with their centers at incommensurate wave vectors at higher temperatures (70 and 120 K). The observed results are consistent with the prediction by recent numerical studies on the S = 1/2 Heisenberg AF chain with competing spin interactions [I. Harada and Y. Aoyama, (1999) “Static spin structure factor of CuGeO3 above spin-Peierls transition temperature”, J. Phys. Chem. Solids 60, 1105; I. Harada, Y. Nishiyama, Y. Aoyama and S. Mori, (2000) “Spin correlation in the one-dimensional Heisenberg antiferromagnet with competing interactions”, J. Phys. Soc. Jpn. 69, (Suppl. A), 339].
