Magnetic susceptibility of Al—Co—R (R = Ce, Dy) glass-forming alloys at high temperatures

The magnetic susceptibility of Al—Co—Ce and Al—Co—Dy amorphous alloys is investigated in a wide range of temperatures ($t = 20$–$1700$ $^\circ$C) and magnetic fields ($B = 0.3$–$1.3$ T). A weak $\chi(B)$ dependence in the entire temperature range and an anomalous increase in susceptibility beginning above the melting temperature of Al$_2$R compound are revealed for all investigated compositions. The experimental data are used to calculate the parameters of the electronic structure of alloys and to estimate the size of super-paramagnetic inclusions. It follows from the experimental data that cobalt atoms are present in these alloys in the nonmagnetic state. It is found that the values of effective magnetic moments on cerium and dysprosium atoms are significantly lower than those for R$^{3+}$ ions and independent of the chemical composition of alloys. The results are discussed assuming the existence in melts of microregions formed by quasi-molecules of Al$_2$R.