The effect of substitution of La for Tb on some physical properties of Tb1−xLaxNi2 solid solutions

The X-ray diffraction performed at room temperature allowed us to reveal that the Tb1−xLaxNi2 solid solutions solidify with the formation of a Laves-phase superstructure corresponding to the F4¯3m space group; no Laves-phase structure is formed. Magnetic measurements showed that the samples with x ≤ 0.8 are ferromagnets with relatively low (below 36 K) Curie temperatures TC. Their Curie temperatures decrease from 36 K for TbNi2 to 8 K for Tb0.2La0.8Ni2. The samples of Tb0.1La0.9Ni2 and LaNi2 have no any long-range magnetic order in measurements temperature range, though the heat capacity measurements suggest a critical La content 90% and TC = 3 K. At high temperatures, all solid solutions are Curie-Weiss paramagnets. The heat capacity measurements have been performed for solid solutions Tb1−xLaxNi2 with x ≤ 0.5 and allowed us to determine the Debye temperature. The magnetocaloric effect was estimated from measurements performed in two magnetic field, 0.42 and 4.2 T.