Influence of MNi2 (M=Sc, Y, La, Lu) compounds on the ferromagnetism of HoNi2–MNi2 solid solutions

Abstract Ferromagnetic properties of HoNi 2 –MNi 2 solid solutions were studied. HoNi 2 is a typical rare earth ferromagnet with the Curie temperature equal to 17.6 K. The source of ferromagnetic order are exchange interaction between magnetic moments of holmium atoms. In the case of solid solutions HoNi 2 –MNi 2 for M=Sc, Y and La, the disappearance of ferromagnetic order has been observed for concentrations of M higher than 60 atomic % whereas for the system HoNi 2 –LuNi 2 the ferromagnetic order is observed even in Lu 0.80 Ho 0.20 Ni 2 solid solution. Values of the magnetic saturation moment μ s for M x Ho 1− x Ni 2 solid solutions with x ⩽0.60 are close to the value of μ s of undiluted HoNi 2 . Moreover, the value of μ s of HoNi 2 suggests that, apart from the contribution of holmium a small contribution of Ni atoms is added. The paramagnetic Curie temperatures Θ are somewhat lower than the values typical of ferromagnets: usually Θ is almost equal to T C . Paramagnetic moments of the solid solutions are similar or higher than that found for pure HoNi 2 . On the basis of the results obtained one may have to state that the influence of the LuNi 2 is the weakest and this compound may be regarded as the best diluter and, in the case of heat capacity measurements, also as the best reference material.