Microscopic model for the magnetic subsystem in HoNi2B2C

Abstract

We demonstrate that the system of localized magnetic moments in HoNi2B2C can be described by the four-positional clock model. This model, at a proper choice of the coupling constants, yields several metamagnetic phases in magnetic field at zero temperature in full agreement with the experimental phase diagram. The model incorporates couplings between non-nearest neighbors in the direction perpendicular to the ferromagnetic planes. The same model leads to a c-modulated magnetic phase near the Curie temperature. The theoretical value of the modulation wave vector agrees surprisingly well with that observed by the neutron-diffraction experiment without new adjustable parameters.