Evolution with applied field of the magnetic structure of TbNiAl 4

Neutron powder diffraction data of TbNiAl 4 has been re-examined using a representational analysis, allowing a new model of the magnetic structure to be deduced. The basis vectors obtained describe an ‘elliptical helix’ type structure in which the moments rotate in the ab -plane as one moves along the c -axis. This new model has been used to simulate the expected result of a Low Temperature Nuclear Orientation (LTNO) experiment involving 299 keV gamma-ray emission from the 160 Dy daughter of aligned 160 Tb nuclei. Results of the simulation along the a -axis appear to partly match currently existing experimental data, with good agreement in the magnitude of lost anisotropy.