Antiferromagnetic square-modulated structure in HoRhSn

The magnetic ordering of HoRhSn, crystallizing in the hexagonal ZrNiAl-type structure, has been investigated by neutron diffractometry in the temperature range between 1.5 and 15.5 K. The compound has been found to order antiferromagnetically below 6 K with a magnetic structure than can be described by a propagation vector k→=[13,13,13]. By group-theoretical analysis it has been shown that this structure corresponds to the irreducible representation τ2τ2. The presence of magnetic Bragg reflections originating from 3k→ propagation vector suggests a square-modulation of Ho magnetic moment instead of the most common sine-modulation. The magnetic moments are oriented along the cc-axis, and at 1.5 K they are equal to 8.78(20)μB8.78(20)μB.