Magnetic behavior of CeFe2: Effects of ruthenium substitution

We report ac-susceptibility measurements on the Laves phase compounds Ce (Fe/sub 1-//sub x/Ru/sub x/)2 with x = 0.02, 0.04, and 0.06. The results show that the ferromagnetic alignment of Fe moments seems to be very easily disrupted by substitution of Ru on the Fe sites. All the three compounds, as well as showing the para- to ferromagnetic transition, indicate another transition at lower temperature. In the case of the x = 0.02 compound, the character of the susceptibility at the lower transition is similar to that seen in reentrant spin glasses, while in the compounds richer in Ru the suppression of the low-field response is much more drastic