Magnetic structure of CeRhIn₅ under magnetic field

The magnetically ordered ground state of CeRhIn₅ at ambient pressure and zero magnetic field is an incommensurate helicoidal phase with the propagation vector k ≤ (1/2,1/2,0.298) and the magnetic moment in the basal plane of the tetragonal structure. We determined by neutron diffraction the two different magnetically ordered phases of CeRhIn₅ evidenced by bulk measurements under applied magnetic field in the basal plane. The low temperature high magnetic phase corresponds to a commensurate sine-wave structure of the magnetization with k ≤ (1/2,1/2,1/4). At high temperature, the phase is incommensurate with k ≤ (1/2,1/2,0.298) and a possible small ellipticity. The propagation vector of this phase is the same as that of the zero-field structure.