MAGNETIC STATE OF INTERMETALLIC HO1-XYX(CO1.95AL0.05)2 COMPOUNDS

In order to investigate the influence of Al atoms on the magnetic prop erties of the RCo2 compounds, neutron diffraction, a.c. susceptibility , thermal expansion and electrical resistivity measurements have been performed on the Ho1-xYx(Co0.95Al0.05)2 compounds. A comparison of thi s system with the Ho1-xYxCO2 compounds with x > x(c) = 0.58 shows that the substitution of Co atoms by Al atoms decreases the critical field which produces the splitting of the d-band. This leads to a long-rang e ferrimagnetic order in Ho1-xYx(Co0.95Al0.5)2 with 0.58 < x < 0.8, wh ile in the Ho1-xYxCo2 compounds the Ho subsystem shows a short-range o rder and the Co subsystem remains paramagnetic.