Crystal structure and magnetic properties of new intermetallic compounds R2MoSi2C (R = Y, Gd-Tm, Lu)

We report the synthesis of novel quaternary silicide carbides R 2 MoSi 2 C (R = Y, Gd, Tb, Dy, Ho, Er, Tm, Lu) and present a systematic study of the phase stability, crystal structure and magnetic properties. These intermetallic compounds crystallize in a tetragonal crystal structure with the P4/mbm space-group symmetry and the evolution of their lattice parameters with the R atomic size follows the lanthanide contraction. It is further found that R 2 MoSi 2 C phase forms only with the heavy rare-earths, starting from Gd with c/a ratio of about 0.6. The systems Lu 2 MoSi 2 C and Y 2 MoSi 2 C show a paramagnetic behavior down to 2 K, whereas the alloys with the magnetic rare-earths (R = Gd-Tm) order antiferromagnetically below 30 K. The magnetic ordering temperature of Tb 2 MoSi 2 C exceeds that of the Gd analog and the Néel temperatures ( T N ) across this series of compounds do not obey the de Gennes scaling. Below T N , the antiferromagnetic ground state gets transformed into a forced ferromagnetic phase via a field-induced metamagnetic phase transition.