MOSSBAUER STUDY ON THE STRUCTURAL AND MAGNETIC-PROPERTIES OF AMORPHOUS BAO-FE2O3-B2O3 SYSTEM

Homogeneous glasses of iron-rich BaO-Fe2O3system (39-63 mol% Fe2O3) with a small amount of B2O3 are prepared by a splat cooling technique. Mössbauer spectra are measured from room temperature to 4.2 K. The room temperature spectrum of the glass with Fe2O3<l consists of a simple paramagnetic doublet, indicating that the glass is formed by Fe 3+ O4 tetrahedral network of fairly uniform configurations. At 4.2 K, a well resolved hyperfine sextet is observed with the internal field of 450 kȮe. The magnetic ordering temperature determined from temperature variation of hyperfine spectrum is 70 K, which is by an order of magnitude lower than that of the corresponding crystalline phase. No evidence for superparamagnetism is observed. The magnetic structure of the glass is suggested to be of short-range antiferromagnetism. Both paramagnetic and hyperfine spectra of the glass with Fe2O3/BAO> are interpreted to consist of the spectra of tetrahedral and octahedral Fe3 +ions. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.