We have measured temperature dependence of low-frequency Raman spectra in CuGeO3, and have observed the quasi-elastic scattering in the (c,c) polarization above the spin-Peierls transition temperature. We attribute it to the fluctuations of energy density in the spin system. The magnetic specific heat and an inverse of the magnetic correlation length can be derived from the quasi-elastic scattering. The inverse of the magnetic correlation length is proportional to (T−TSP)1/2 at high temperatures. We compare the specific heat with a competing-J model. This model cannot explain quantitatively both the specific heat and the magnetic susceptibility with the same parameters. The origin of this discrepancy is discussed.
@article{arxiv.cond-mat/9610134,
title = {Spin fluctuations in CuGeO$_3$ probed by light scattering},
author = {Haruhiko Kuroe and Jun-ichi Sasaki and Tomoyuki Sekine and Naoki Koide and Yoshitaka Sasago and Kunimitsu Uchinokura and Masashi Hase},
journal= {arXiv preprint arXiv:cond-mat/9610134},
year = {2009}
}
Comments
17 pages, REVTeX, 5 Postscript figures; in press in PRB