[en] A survey is presented on the occurrence of itinerant-electron magnetism in actinide metals with emphasis on the uranium Laves phase- and the uranium-platinum compounds. The Laves phase compounds can be understood with concepts of magnetism that have been developed for the transition metals, including that of spin fluctuations. The absence of magnetic order in most of the uranium-platinum compounds in combination with large values for the coefficient of the electronic term in the specific heat points to a strong hybridisation of f and d electron states. The magnetic order of UPt is complex and can not simply be represented by an itinerant-electron model. (Auth.)

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[en] A survey of pressure effects on magnetic order, spin fluctuations and superconductivity in the uranium intermetallics is presented. In the limit of localized 5f electrons, pressure effects on the spontaneous magnetic moment are found to be weak, whereas in the itinerant case magnetism is appreciably suppressed by increasing pressures. Several of the uranium intermetallics combine superconductivity with large values for the coefficient of the electronic term in the specific heat. In this class of ''heavy fermion'' superconductors, positive as well as negative pressure effects on the superconducting transition temperature have been found. In the analysis of the high-pressure data, special attention is paid to magnetic order in UNi₂ and superconductivity in UPt₃. (orig.)

[en] A review is presented of the anomalous magnetic and superconducting properties of the heavy-fermion compound UPt₃ that has been a subject of extensive study during the past twenty years. The normal state and superconducting properties of the compound were evaluated from magnetic, transport and thermodynamic studies. In addition, neutron-diffraction and muon spin relaxation experiments were performed in the normal and superconducting states. The compound is characterized by a multiple superconducting phase diagram and by the coexistence of superconductivity and short-range antiferromagnetic interactions with quasi-static moments of the order of 10^-2 μ_B.U-atom. Upon substituting Pt by Pd, the short-range magnetic interactions give way to long-range antiferromagnetic order and with a maximal ordering temperature of 6 K for the 5 at.% Pd alloy and a magnetic moment of 0.6 μ_B/U-atom. Superconductivity and long-range antiferromagnetic order are in competition resulting in a critical composition of 0.6 at.% Pd. At this concentration, non-Fermi liquid behaviour is observed. (author)

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[en] The easy direction of magnetization in gadolinium has been found to be situated at normal pressure in the basal plane in the temperature interval between 100 K (T₁) and 250 K (T₂). The two transition temperatures T₁ and T₂ are strongly pressure dependent: deltaT₁/deltap approximately =-10 K/kbar and deltaT₁/deltap approximately =-6 K/kbar. (Auth.)

[en] Recent results regarding the magnetic and electrical properties of UPt under high pressures are presented, together with the results of neutron diffraction and neutron depolarisation studies. The experiments point to two different magnetic phases in UPt with ordering temperatures of 19 and 27 K, respectively. Internal stresses and oxide content determine the amount in which each of these two phases is present in a particular sample. The magnetic phase with the ordering temperature of 27 K exhibits a ferro- to antiferromagnetic transition at 4 kbar. This antiferromagnetic phase is characterised at 4.2 K by a metamagnetic transition at a field of 3 t. (orig.)

[en] We briefly overview the highlights of some of the experimental papers presented at SCES'02

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No abstract available