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 6T 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 0.2μB (at 2K) cause a magnetic contribution to be of Gaussian type.