Evidence for crystal-lattice modulation due to spatially restricted enhancement of mixing effect in the low-carrier system CeSb

In order to investigate the unusual magnetic properties of the low-carrier system CeSb, X-ray diffraction studies at low temperatures have been performed. Below the magnetic transition temperature of T-N = 17K, several X-ray satellite peaks and their temperature variations were observed, which indicate that the modulated structures of a crystal lattice coexist with the long-period magnetic structures in CeSb. The observed wave numbers of the lattice modulations and the satellite-peak intensities are explained by the periodical arrangement of short and long distances between magnetic layers. The short interlayer distance is due to enhancement of p-mixing effect which is spatially restricted within the ferromagnetic layers of Gamma(8)-like Ce ions appearing in the lattice of Gamma(7) Ce ions. The interlayer distance due to Gamma(8)-like state is shorter la 0.1% than that between normal Gamma(7) Ce layers.