MAGNETIC-PROPERTIES OF FE3SN2 .2. NEUTRON-DIFFRACTION STUDY

For pt.I see Act Crystallogr., vol.B32, p.1348 (1976). The intermetallic compound Fe3Sn2 has been studied by neutron diffraction and magnetisation measurements. This compound is ferromagnetic (T C=657K). At room temperature the spin direction is along the c axis. A spin rotation is observed between approximately 250 and 60K. Below 60K the spin direction lies in the (001) plane. A consistent fit of the neutron diffraction pattern is only obtained by a modification of the magnetic form factor of Shull and Yamada (1962). This modification means that the spin carriers are delocalised in the 'Fe-Sn' planes while they are localised along the c axis. The variations of the 57Fe anisotropic hyperfine fields (from Mossbauer effect measurements) and the mechanisms which predominantly determine the tin hyperfine fields in the series Fe3Sn-Fe 3Sn2-FeSn are discussed.