ON THE MAGNETIC-BEHAVIOR OF ACO2 (A = Y, LU, ZR, SC AND HF) COMPOUNDS

The magnetic properties of ACo2 (A = Y, Lu, Zr, Sc, Hf) compounds were investigated in the temperature range 2-1100 K and fields up to 70 kO e. In order to avoid a possible alteration of the magnetic susceptibil ities, chi, caused by the presence of magnetic ordered impurities, the chi values were obtained from magnetization isotherms, by extrapolati on to H--1 --> 0. At high temperatures, the ACo2 (A = Y, Lu, Sc and Hf ) compounds show temperature dependences of magnetic susceptibilities of Curie-Weiss type. In ZrCo2, a more complex thermal variation of mag netic susceptibility is evidenced. At T less than or similar to 15 K, the chi values for YCo2 and LuCo2 vary according to the relation chi = chi0(1 + aT2). The experimental data are analysed in the spin fluctua tions model.