VERY WEAK ITINERANT FERROMAGNETISM IN THE NEW LU3CO8-XSN4 COMPOUND (X=0.23)

The crystal structure of the new compound Lu3Co8-xSn4 (x = 0.23) was d etermined by using a single-crystal diffraction method. The structure of Lu3Co8-xSn4 is a distorted variant of the BaLi4 structure type: spa ce group P6(3)mc, a = 8.746(3) Angstrom, c = 7.432(2) Angstrom, Z = 2. The coordination number of the lutetium atom is 18; for the tin and c obalt atoms the coordination polyhedra are either distorted icosahedra or trigonal prisms. The magnetic properties of Lu3Co8-xSn4 are presen ted and discussed. This compound is a typical very weak itinerant ferr omagnet with T-c = 63 K and a Co moment of 0.19 mu(B) at 4 K, whereas the effective paramagnetic moment reaches 1.86 mu(B)/Co.