Evolution of the magnetic properties in the antiferromagnet CeRhIn simultaneously doped with Cd and Ir.

We report the evolution of the magnetic properties of single crystals. In particular, for () and (), we have solved the magnetic structure of these compounds using single-crystal neutron magnetic diffraction experiments. Taking the magnetic structure of the heavy-fermion antiferromagnet as a reference, we have identified no changes in the magnetic wave vector; however, the direction of the ordered Ce moments rotates toward the plane, under the influence of both dopants. By constraining the analysis of the crystalline electric field (CEF) with the experimental ordered moment's direction and high-temperature magnetic-susceptibility data, we have used a mean-field model with tetragonal CEF and exchange interactions to gain insight into the CEF scheme and anisotropy of the CEF ground-state wave function when Cd and Ir are introduced into . Consistent with previous work, we find that Cd doping in tends to rotate the magnetic moment toward the plane and lower the energy of the CEF excited states' levels. Interestingly, the presence of Ir also rotates the magnetic moment towards the plane although its connection to the CEF overall splitting evolution for the = 0 samples may not be straightforward. These findings may shed light on the origin of the disordered spin-glass phase on the Ir-rich side of the phase diagram and also indicate that the compounds may not follow exactly the same Rh-Ir CEF effects trend established for the compounds.