Crystal structures and magnetic properties of new quaternary sulfides BaLn(2)MS(5) (Ln = La, Ce, Pr, Nd; M Co,Zn) and BaNd2MnS5

Crystal structures and magnetic properties are investigated for new quatern ary sulfides BaLn(2)TS(5) (Ln=La, Ce, Pr, Nd; T=Co, Zn) and BaNd2MnS5, Thes e compounds crystallize in a tetragonal structure (space group I4mcm), whic h is isostructural with BaLa2MnS5. Their lattice parameters increase monoto nically with the sizes of the lanthanide and transition metal. The increase of the a values is mainly due to the lanthanide size, and that of the c va lues is due to the transition metal size, In BaLn(2)CoS(5), the Co2+ ions h ave the unquenched orbital moments. In BaNd2MnS5 the magnetic anomaly due t o the antiferromagnetic ordering of the Mn2+ ion, is found at 63 K, Antifer romagnetic orderings for the Co2+ ions are observed at ca. 65 K in BaLn(2)C oS(5) (Ln = La, Ce, Pr, Nd). For BaNd2TS5 (T=Mn, Co, Zn), the Nd3+ ions als o show antiferromagnetic behavior below 6 K. (C) 2001 Academic Press.