Magnetic structures of rare earths R in RCoC2 and RNiC2 compounds

A comparative survey is given on the variety of magnetic structures of the series of RCoC2 and RNiC2 with R = Pr, Nd, Tb, Dy, Ho, Er and Tm, which have been analysed by neutron diffraction. Rare earth structure relevant features are summarized. All compounds, except those with Pr, order magnetically at low temperatures. Magnetic order is confined to the rare earths; Co and Ni sites remain non-magnetic. RCoC2 become ferromagnets; RNiC2 order antiferromagnetically in different spin configurations. The type of order and R dependent moment configurations are explained by RKKY exchange and additional crystal field interactions.