A generic phase diagram for R₂PdSi₃ (R = heavy rare earth)?

The magnetic phase diagrams of hexagonal R₂PdSi₃ compounds have been found to feature an apparent similar phase when the field is applied along the respective magnetic easy axes. To elucidate this, neutron diffraction on single crystalline Tb₂PdSi₃ and Ho ₂PdSi₃ in magnetic fields was performed. These two compounds have different magnetic structures in zero field. In Tb ₂PdSi₃ the propagation vector is parallel to the hexagonal axis while in Ho₂PdSi₃ the propagation is in the basal plane. In both compounds the magnetic moment direction is perpendicular to the propagation vector. The application of a magnetic field along the respective easy axes destroys the zero field magnetic structure and leads to a ferrimagnetic phase with magnetic intensity on the same positions for both compounds. These findings and their connections to the crystallographic (super-)structure are presented and discussed.