Structural and magnetic properties of Sc sub(1.1Fe) sub(3).9Al sub(8 alloy)

The crystallochemical and magnetic nature of ternary Sc sub(1+[delta]Fe) sub(4)-[delta]Al sub(8 intermetallic with a small Sc excess [delta]=0.1 was investigated by scanning electron microscope, X-ray powder diffraction, neutron diffraction, Moessbauer effect and superconducting quantum interference device techniques. The sample crystallizes in a tetragonal ThMn) sub(1)2 type structure. The excess of Sc atoms substitute Fe at the (8f) positions and have a pronounced effect on the magnetic properties. The experiments carried out in temperature range 4-320 K show that below 120 K the magnetic structure of the alloy forms a double cycloid with magnetic moments rotating according to the incommensurate in-plane wave vector, which is temperature independent up to 160 K. The value of Fe magnetic moment is close to 0.9 [micro] sub(B atom[super]-1 at 4 K. Temperature dependence of unit cell dimensions can be explained within the Debye-Grueneisen approximation.)