The magnetic properties of ACo2 (A = Y, Lu, Zr, Sc, Hf) compounds were investigated in the temperature range 2–1100 K and fields up to 70 kOe. In order to avoid a possible alteration of the magnetic susceptibilities, χ, caused by the presence of magnetic ordered impurities, the χ values were obtained from magnetization isotherms, by extrapolation to H-1→0. At high temperatures, the ACo2 (A = Y, Lu, Sc and Hf) compounds show temperature dependences of magnetic susceptibilities of Curie-Weiss type. In ZrCo2, a more complex thermal variation of magnetic susceptibility is evidenced. At T ⪅ 15 K, the χ values for YCo2 and LuCo2 vary according to the relation χ = χ0(1 + aT2). The experimental data are analysed in the spin fluctuations model.
The results of magnetic measurements performed on U x La 1− x Al 2 and U x Y 1− x Al 2 compounds are reported. Above ∼ 60 K, the temperature dependences of susceptibilities were analysed assuming a superposition of a temperature dependent term on a Pauli-type contribution. The paramagnetic Curie temperature, θ, decrease in absolute magnitude by increasing La or Y content. The effective moments per U atom vary from 3.06 μ B for x = 1.0 up to 2.60 μ B for x = 0.2. The experimental data were analysed in correlation with the separation between the uranium ions.
The results of magnetic measurements performed on U(Mn x Al 1−x ) 2 compounds in the temperature range 4.2K < T < 800K are reported. In the low temperature range ( T < 200K), UMn 2 shows a Pauli-type paramagnetism. Above 420K a Curie-Weiss behaviour is evidenced. The magnetic properties of U(Mn x Al 1−x ) 2 compounds were analysed assuming a superposition of a temperature dependent term on a Pauli-type contribution, χ O . The effective moments as well as the χ O values were determined both in the low ( T < 200K) and high ( T > 420K) temperature range. The experimental data were discussed considering changes in the band structure and/or quenching of spin fluctuations.
The temperature dependence of the electrical resistivity ϱ of binary R6Mn23, R6Fe23 (R = Y, Dy, Ho, Er, Tm) and pseudobinary R6(Fe1-xMnx)23 (R = Y, Er, Ho) compounds has been determined by a four-probe measuring technique in the temperature range 4 to 400 K.
