11:15 AM - 11:30 AM
[19a-E201-10] Neutron diffraction study of the magnetic structure of metamagnetic MnAl alloy
Keywords:metamagnetism, neutron diffraction, manganse alloys
The ferromagnetic L10-MnAl (τ-phase) is metastable phase with a Mn content of 55–60 at%. Recently we have reported that a τ-phase with nearly stoichiometric composition with higher ordering parameter was obtained by post-annealing of electrodeposited MnAl powder and it showed metamagnetism. However, the mechanism of metamagnetism is still unclear. In order to clarify the mechanism, the magnetic structure of t-phase was investigated by neutron diffraction. Consequently, ferromagnetic peaks (d = 1.9, 2.2 Å) were not observed. However, several magnetic peaks were observed. By Rietveld analysis, we concluded these peaks result from 6-fold magnetic superstructure along the c-axis of t-phase. In this presentation, we will discuss about the model of the magnetic structure deduced by Rietveld fitting in detail.