The field-induced magnetic structure in UIrGe

We have investigated the field-induced ferromagnetic phase in UIrGe by means of neutron diffraction in fields up to 14.5 T applied along the c-axis. At 2 K, the ground-state antiferromagnetic structure of UIrGe (non-collinear with a non-zero hard-axis antiferromagnetic component) transforms into a simple ferromagnetic structure above a critical field of 14.2 T applied along the c-axis. The value of the U moment amounts to 0.36(8) muB, in good agreement with the zero-field value. This result shows that the anisotropic interactions along the a-axis are weaker than the isotropic ones.