Molten metal flux growth and characterizations of a new compound PrRh4.8B2single crystals

The hexagonal plate-like single crystals of a new compound PrRh4.8B2 were o btained by a molten metal flux growth method using Cu as a flux. PrRh4.8B2 is orthorhombic with the space group Fmmm; a=0.9697(4) nm, b=0.5577(2) nm a nd c=2.564(3)nm. The structure of the compound is of a modified CeCo3B2-typ e which is explained by a stacking model of Pr-B and rhodium layers. The te mperature dependence of inverse static magnetic susceptibility, chi(-1) obe ys the Curie-Weiss law at higher temperature above 50 K. The mu(eff) is 4.2 mu(B) and Theta(p) is -13 K. The value of the observed effective magnetic moment is larger than the value of 3.6 mu(B) for the free trivalent ion Pr3 +. The susceptibility deviates from the Curie-Weiss law, below 50 K, sugges ting some magnetic ordering. The value of MVH for c-plane with the orthorho mbic symmetry of PrRh4.8B2 is 6.7+/-0.6 GPa. The TG curve represents that o xidation of the PrRh4.8B2 proceeds above 600 degrees C. Weight gain of the specimen heated up to 1200 degrees C in air is 13%. After TG-DTA measuremen t, final product is PrBO3 and Rh. (C) 1999 Elsevier Science S.A. All rights reserved.