Magnetic, electrical, and thermodynamic properties of the LaxHo1−xNi2 solid solutions

Results of X-ray diffraction analysis of polycrystalline solid solutions LaxHo1−xNi2 and measurements of their magnetization, electrical resistivity, and heat capacity are reported. The X-ray diffraction patterns indicate that, at room temperature, the compounds have the C15-type Laves-phase superstructure. The substitution of the lanthanum for holmium markedly modifies the ferromagnetic ordering and destroys it as the lanthanum content increases to x = 0.8. The Curie temperatures of the solid solutions decrease linearly from 17.6 K for HoNi2 to 5 K for La0.6Ho0.4Ni2. At high temperatures, all the solid solutions are Curie-Weiss paramagnets. The temperature dependences of the electrical resistivity exhibit a behaviour typical of metals. The heat capacity measurements allowed us to determine the Debye temperature. The magnetocaloric effect was estimated from measurements performed in a low magnetic field of 0.42 T.