Studies on Magnetic Excitation Spectra of High-T_c Superconductors (Condensed Matter : Electronic Structure, Electrical, Magnetic and Optical Properties)

概要

論文の詳細を見る
Magnetic excitation spectra X"(q, ω) of YBa_2Cu_3O_y, La_<2-x>Sr_xCuO_4, La_<2-y-x>Nd_ySr_xCuO_4 and Nd_<2-x>Ce_xCuO_4 are compared with those of model calculations, where q and ω are the wave vector and the energy of the excitations. In the model, the dynamical spin susceptibility is calculated by the expression X(q, ω) = X_0(q, ω)/{1 + J(q)X_0(q, ω)}, where X_0(q, ω) is obtained by adopting the effective energy dispersion of the quasi particles which can reproduce the shapes of the Fermi surface, and J(q) is the exchange coupling between the Cu-Cu electrons. It is important to consider the experimentally observed quasi particle broadening (Г) to reproduce the observed spectra of YBa_2Cu_3O_y, while to reproduce the data of La_<2-x>Sr_xCuO_4 and La_<2-y-x>Nd_ySr_xCuO_4, very small F values have to be used, even in the phases without the static "stripe" order. This may be caused by the existence of the "stripe" correlations or "stripe" fluctuations.
社団法人日本物理学会の論文
2004-04-15