Temperature-induced itinerant metamagnetism in R1−xYxCo3 systems (R=Ho, Tb)

Abstract The thermal expansion of pseudobinary Tb 1− x Y x Co 3 and Ho 1− x Y x Co 3 systems has been measured by X-ray diffraction in the temperature range 8–700 K. In the Ho-system, a temperature-induced itinerant electron metamagnetism is observed in the concentration range 0.5⩽ x ⩽0.0 where the Co sublattice is in the strong ferromagnetic state at low temperatures. In contrast, the transition is smeared out in the Tb 1− x Y x Co 3 compounds, and the unit cell volume changes smoothly below T C at any Y concentration. Due to the large anisotropic magnetostriction of the Tb 3+ -ions, the Tb-based compounds show orthorhombic lattice distortion of the order of 10 −3 : (b r / 3 −a r )/a r =3.9×10 −3 in TbCo 3 . The distortion decreases linearly with increasing x pointing at zero for x =1, which indicates the dominating contribution of the Tb sublattice to the anisotropic magnetostriction.