The magnetic phase diagram of the tetragonal Ho2RhIn8 compound has
similar features to many related systems, revealing a zero magnetic field AF1
and a field-induced AF2 phases. Details of the magnetic order in the AF2 phase
were not reported yet for any of the related compounds. In addition, only the
Ho2RhIn8 phase diagram contains a small region of the incommensurate
zero-field AF3 phase. We have performed a number of neutron diffraction
experiments on single crystals of Ho2RhIn8 using several diffractometers
including experiments in both horizontal and vertical magnetic fields up to 4
T. We present details of the magnetic structures in all magnetic phases of the
rich phase diagram of Ho2RhIn8. The Ho magnetic moments point along the
tetragonal c axis in every phase. The ground-state AF1 phase is characterized
by propagation vector k = (1/2, 0, 0). The more complex
ferrimagnetic AF2 phase is described by four propagation vectors
k0 = (0, 0, 0), k1 = (1/2, 0, 0), k2
= (0, 1/2, 1/2), k3 = (1/2, 1/2, 1/2). The magnetic structure in
the AF3 phase is incommensurate with kAF3 = (0.5, δ, 0).
Our results are consistent with theoretical calculations based on crystal field
theory.Comment: submitted to PR