Mössbauer Effect and Magnetic Properties of Iron-Beryllium Compounds

Abstract

Mössbauer measurements using Fe57 were made on the Fe–Be system in the composition range between 66 and 85 at. % Be. The internal field and the isomer shift in FeBe2 (66.7% Be, MgZn2 structure) are 192±5 kOe and 0.13±0.05 mm/sec, respectively. A metallic iron standard at room temperature was used. The Mössbauer spectrum of a single crystal of FeBe2 shows that the magnetization is parallel to the c axis. When the Be concentration is increased above 66.7%, two or more internal fields are observed, corresponding to Fe (4), Fe (3), and so on. Fe (4), Fe (3), etc., are defined as Fe atoms which have 4, 3 Fe atoms, respectively, in the nearest-neighbor iron sites. When the Be concentration exceeds 75%, the MgCu2 crystal structure develops and the materials are paramagnetic. The (Fe–Mn) Be2 system was also investigated. It was found that the presence of nearest-neighbor Mn atoms decreases the field at the iron sites by approx 14%.