W. Steiner

57Fe Mössbauer studies on BaFe2X3 compounds with X = S, Se

57Fe Mossbauer investigations are reported for BaFe2X3 compounds with X = S, Se in the temperature interval 4 < T < 293 K. According to temperature dependence of quadrupole splitting and value of centre shift both samples can be characterised as mixed valence compounds. Whereas at 4.2 K for the sulphur compound only one hyperfme split spectrum is present, a field distribution with approximately a factor of two larger mean hyperfme field is observed for the Se sample.

Influence of segregation on magnetic order in Cr75(Fe x Mn1−x)25, 0.64 ≤x ≤ 0.85

Mössbauer and magnetic measurements on Cr75(Fe,Mn)25 alloys, which were segregated and re-disordered by appropriate heat treatments, are reported. A primary factor for the kind of magnetic order which appears is the Cr concentration around the Mössbauer probe atom. At around 15 K, a transition to a re-entrant spin-glass state occurs. For this state, the hyperfine field distributions of all investigated disordered and re-disordered samples are independent of the Fe concentration.

High field Mössbauer measurements on CeFe2 and Ce(Fe0.965 Al0.035)2

Magnetization and high field Mössbauer experiments were performed to study the ground state and the metamagnetic transition in Ce(Fe, Al)2. A model is proposed for the arrangement of the Fe-moments which includes the reported finite Ce-moment.