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Crystal structures are studied in a series of alloys in the Y6Fe(1−x Alx)23 system. The binary phase Y6Fe23 (of Th6Mn23 structure) is confirmed. The phase boundary by Al substitution is located at 20 at% Al. The magnetic properties are studied by means of magnetization measurements in fields up to 60 kOe for 0 ≦ x ≦ 0.20. The Curie temperatures and the mean magnetic moments decrease with increasing × values; this decrease is qualitatively discussed in a localized model.

The effect of atomic short-range order (SRO) in Cu-Mn (5-30 at.% Mn) on the spin-glass properties is studied by measuring the magnetic behaviour and the low-temperature specific heat for two well defined equilibrium states of SRO. Usual spin-glass features are observed. The freezing temperatures Tf as well as the coefficient gamma * of the linear specific heat term appear to be not sensitive to SRO, whereas the amplitude of the peak susceptibility at Tf is drastically increased. The results are compared with previous work after different thermal treatments.

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Atomic short-range order in CuMn alloys (5-30 at% Mn) in equilibrium state is studied as well as its effect on the magnetic behaviour and low temperature specific heat. Spin glass features are observed and the freezing temperature Tf appears to be not sensitive to SRO as well as the linear specific heat term γ*T whereas the amplitude of the susceptibility peak at Tf is drastically increased

Magnetic hysteresis losses in V2Zr and V2Hf Laves phase compounds are investigated. The influence of the geometrical shape, first penetration field and that of the flux creep phenomenon is considered. The hysteresis at static magnetization is calculated for a set of values of the parameter γ describing magnetic induction profile and compared with observed data. The best fit value depends on the ordering state of the sample.