Phase diagrams of anisotropic ferrimagnet HoCo3Ni2 with Tcomp=TSR1

The magnetic phase diagrams of the hexagonal intermetallic ferrimagnet HoCo₃Ni₂ showing the spin reorientation transition are presented. The diagrams have been calculated from the thermodynamic potential including the exchange energy as well as the anisotropy energy, taking into consideration the second and fourth-order anisotropy terms. The obtained phase diagrams differ substantially from those of the isotropic or uniaxial ferrimagnets. In fields parallel to the basal plane, the new cone-canting phase with constant susceptibility has been found in the spin reorientation range. In fields parallel to the hexagonal axis there exists a narrow link between low and high-field canted phases. The existence of the new cone-canting phase has been confirmed by magnetization measurements on a single crystal using both ballistic and SQUID magnetometers