The structure and uniaxial magnetocrystalline anisotropy of novel intermetallic compounds La2Co17-xVx

The crystal structure and magnetic properties of new intermetallic compounds La2Co17-xVx (0.8 less than or equal to x less than or equal to 1.2) have been investigated by x-ray powder diffraction and magnetic measurement. The lattice parameters of La2Co17-xVx with the rhombohedral Th2Zn17-type structure are a = 8.4971-8.5006 Angstrom, c = 12.3370-12.3424 Angstrom. V atoms show a strong preference for occupying 6c crystallographic positions. The La2Co17-xVx compounds are ferromagnetic. The Curie temperature decreases from 926 to 827 K and the saturation magnetic moment decreases from 22.5 to 19.6 mu(B) fu(-1) with x = 0.8-1.2. The La2Co16V compound exhibits favourable uniaxial anisotropy and the easy magnetization direction is parallel to the c axis. The anisotropy field is 19 kOe at 1.5 K for the La2Co16V compound. The reasons that La2Co17 does not exist and La2Co16V has uniaxial anisotropy are discussed.