Debye temperatures and magnetic structures of UFexAl12-x (3.6 <= x <= 5) intermetallic alloys

Uranium ternary compounds UFexAl12-x crystallize in a body-centred tetragon al structure ThMn12 (I 4/mmm No,139), The neutron powder diffraction, magne tization measurements as well as Mossbauer investigations clearly indicate the magnetic ordering within the iron sites. The rearrangement of iron magn etic moments from uncompensated antiferromagnetics system in UFexAl12-x wit h x < 4, through coexistence of antiferro- and ferrotnagnetic iron componen ts (4 less than or equal to x < 5) to pure ferromagnetic ordering for alloy with x = 5 is observed, The neutron diffraction studies of magnetic struct ures of the aforementioned powder samples show a very rich world of possibl e uranium-iron magnetic interactions. For all these alloys the magnetic neu tron scattering is generally weak in comparison to the nuclear one. Because of identical chemical and magnetic unit cells there are no pure magnetic r eflections. Therefore, in order to extract magnetic part of the scattering one should be particularly careful in taking proper account of the thermal vibration effects, (C) 2000 Elsevier Science B.V. All rights reserved.