Evolution of magnetic properties in the solid solution DyCo1âˆ’Ñ NiÑ C2

The crystal structure of the solid solution of DyCo1−хNiхC2 (0≤x≤1) was investigated by means of X-ray powder diffraction: structure type CeNiC2, space group Amm2, and Pearson symbol oS8. The structural analysis reveals a non-monotonous evolution in particular for the a- and c-lattice constants resulting in a non-linear increase of the unit cell volume due to non-isoelectronic substitution of Co by Ni markedly deviating from Vegard׳s law. A crossover from ferro- to antiferromagnetic ordering with a significant reduction of the magnetic ordering temperature at intermediate compositions in DyCo1−хNiхC2 is observed when varying the Ni-concentration. A crossover from ferro- to antiferromagnetic coupling is also revealed from a sign change of the paramagnetic Curie temperature when proceeding along this solid solution.