Influence of cr-atoms on the magnetic and electrical properties in Ho(Co1-xCrx)2 compounds

AC magnetic susceptibility, electrical resistivity and X-ray Photoelectron Spectroscopy (XPS) measurements have been performed on the Ho(Coi_a,Cra,)2 compounds with x=0.0, 0.03, 0.05, 0.10, 0.15 and 0.20. A strengthening of the HoCo2 ferrimagnetism shows up through a rapid increase at small Cr concentration x of the Curie temperature Tq which reaches a maximum around x= 0.15. The lattice parameters also go through a maximum for the same concentration of Cr. A remarkable decrease of the density of states near the Fermi level is observed for the sample with x= 0.20. We correlate the changes of the Curie temperature with the decrease of d-electron concentration when Cr substitutes for Co[…