Magnetic Properties and Magnetic Structure of Amorphous Oxides in FeO_x-CaO-SiO₂ System

Abstract

The amorphous phase region is located in a narrow area near the side of CaO-SiO₂. The magnetization of amorphous oxides is very small at the room temperature, but markedly increases for temperatures lower than about 50 K. The room temperature Mössbauer spectra indicate paramagnetic peaks. The spectra at 77K reveal six weak Zeeman peaks buried in the background. At 4.2 K, a well resolved hyperfine sextet is observed. The Mössbauer results suggest that the Fe atoms are distributed inhomogeneously in the solid and that the structural short-range order around Fe atoms is very strong, having random bonding and distance fluctuation.