Antiferromagnetic structure in UNiAl at dilution temperatures

Neutron diffraction experiments in zero field reveals that the originally sine wave modulated antiferromagnetic structure in UNiAl starts to square up at low temperatures. The squaring up is, however, not completed even at 150 mK, most probably due to competing magnetic interactions. The fact that the magnetic moments are not equal at all the uranium atomic sites is responsible at least partially for the enhanced low temperature specific heat coefficient observed in UNiAl at low temperatures

Magnetic properties of UNi2 3Rh1 3Al single crystal probed by polarized neutron diffraction

A delicate balance between ferromagnetic and antiferromagnetic interactions in URh1 3Ni2 3Al leads to the absence of a long range magnetic order and anomalous bulk properties of this material in zero magnetic field. The reported polarized neutron diffraction experiment in fields up to 6 T indicates that the positional dependence of Ni Rh atomic distribution is responsible for the abnormal zero field profiles most reflections have a significant Lorentzian contribution , while the field induced U moments of 0.2 B at 2 K cause a magnetic contribution to be of Gaussian type

On the magnetic structure of UIrGe

Although all the bulk properties of UIrGe point to an antiferromagnetic AF ordering below 16 18 K, several neutron diffraction experiments failed to solve the magnetic structure of this compound. Neutron diffraction at low temperatures on a newly grown UIrGe single crystal revealed a weak magnetic signal on top of very few nuclear reflections. Refinements to models allowed by symmetry show that a commensurate, non collinear antiferromagnetic structure exists in UIrGe. U magnetic moments are strongly reduced and amount at 1.8 K to 0.36 8 amp; 956;B