Magnetic properties of the icosahedral Cd-Mg-rare-earth quasicrystals

We report de and ac magnetization of the newly discovered Cd-Mg-RE quasicrysrals (RE = Gd, Tb, Dy, Ho, Er, Tm and Yb). For all the RE atoms except Yb, the temperature dependence of the de magnetization obeys the Curie-Weiss law at higher temperatures, T > 50 K. Estimated effective moments indicate that these atoms are in the trivalent states. In contrast, the Cd-Mg-Yb quasicrystal shows very small magnetization, suggesting that Yb is in the non-magnetic divalent state. At lower temperatures, spin-glass-like freezing was observed for the RE atoms except Tm and Yb. In particular, the freezing proceeds in two successive steps for RE Cd, Tb, Dy and Ho, being quite different from canonical spin-glasses.