Magnetic properties of the Tb2+xCo17−ySiy alloys

The structure and magnetic properties of four polycrystalline alloys from the Tb2.1Co17 -ySiy system have been investigated at temperature range 4.2-1100 K in various magnetic fields. The field dependence of magnetisation at T = 4.2 K up to 140 kOe has been measured using a string magnetometer and up to 370 kOe in pulsed magnetic field, with a pulse duration of 10 ms. The aim of this research was to establish the influence of the alloys stoichiometry and composition change on the structure and the magnetic properties. The substitution of Si for Co introduced considerable disorder into pristine Tb-Co17 compound with the Th2Ni17-type hexagonal structure and decreased Curie point from Tc > 1100 K for y = 0 to 623 K for y = 3. Also "saturation" magnetisation decreases from about 15mB for y = 0 to 10.4mB for y = 3 in the highest applied field. Therefore, an admixture of Si does not improve the magnetic properties of the investigated alloys.