[摘要]：The synthesized (Bi(1.88)Fe(0.12))(Fe(1.42)Te(0.58))O(6.87) is characterized with so far the highest Fe content among pyrochlores. Consequently, it exhibits a strong spin-glass magnetic transition at around 20 K The dielectric relaxation in the same temperature range originates from multiwall hopping of the displaced ions on A and O' sites. The displacement was confirmed with the structural analysis of the pyrochlore using Rietveld refinement on joint neutron and X-ray diffraction data. At room temperature, the pyrochlore exhibits a cubic Fd (3) over barm symmetry (a = 10.38804 (13) angstrom) with Fe(3+) ions sharing A and B structural sites. The refined results indicate on a displacive disorder with A-site positioned at 96g and O' positioned at 32e. The lattice vibrational analysis using Raman spectra is in agreement with the displacive disorder of the pyrochlore.
