[en] A neutron-diffraction study of isostructural ErNi_1-xCu_xAl compounds is reported. A change of magnetic ordering, from antiferromagnetic (AF) to ferromagnetic, and a change in the type of magneto-crystalline anisotropy are found. A discontinuity of the lattice parameters on entering the ordered state is confirmed. An AF ordering of the Er moments within the basal plane is observed for x≤0.4. An additional incommensurate propagation with moments aligned along the c-axis appears for x increasing beyond 0.2, accompanied by a weakening of the (a,b)-plane component. The moments in ErNi_0.5Cu_0.5Al ferromagnetically align along the c-axis. A short-range magnetic ordering is observable for x=0.6 and 0.8

[en] DyNiAl orders ferromagnetically below T_C=30 K with the Dy magnetic moments oriented along the hexagonal c-axis, and undergoes an order-order magnetic phase transition at T₁=15 K where an antiferromagnetic component appears in the basal plane leading to a non-collinear magnetic structure. Magnetization measurements on a DyNiAl single crystal in fields up to 40 T revealed a large uniaxial magnetic anisotropy with anisotropy field of 25 T and field-induced transitions in fields applied along the basal plane. A low-field transition is observed in both magnetic phases and is associated with a rotation of the total magnetic moment toward the field direction to form a canted magnetic structure, which is stable in a wide field interval. A high-field transition is observed only in the low-temperature phase and corresponds to a spin flop of the antiferromagnetic component

[en] Programs are listed included in the package under study which were applied in test calculations of static strength, temperature fields, local temperature stress during transients, stress in a pipe bend, the effects of seismic actions, the assessment of fatigue strength, etc. The calculation is separated into six stages and ends with a program for graphic output preparation. The principles of program integration, program upgrading, the check of the correctness of calculations, and the experience gained so far during the construction of nuclear power plants are described. (J.C.)

[en] The fabrication of 6 heat exchangers for the new nuclear power plant at Temelin was successfully finished by the Kralovopolska Company in August 1993. All parts of the emergency cooling exchangers that will get into contact with the water coolant will be fitted with two-phase steel. The exchanger design is based on the AO 257 572 heat exchanger with helical partitions. The advantage of this patented solution is a significant intensification of the heat exchange at a minimum loss in pressure, which makes it possible to use tubes of a smaller diameter. The simplicity of this solution leads to a reduction in the number and length of welded joints and thus increases the reliability. (M.D.)

[en] Demands placed on the implementation of calculations of pipe strength used in testing nuclear power plants piping show that each pipe system must be checked using several programmes. From this ensues the necessity of interlinking the programmes and developing a comprehensive set of programmes. Recommendations are given as to what should be given priority attention. (J.P.)

[en] The RNi_1-xCu_xAl pseudoternaries belong to group of RTX intermetallic compounds crystallizing in the hexagonal ZrNiAl type of structure. In the critical region of the substitution parameter x ∼ 0.8 there was found a loss of a long-range magnetic order at the lowest studied temperatures for series with R = Tb, Dy, Er. As an explanation for this effect a competition of different ordering mechanisms for either RNiAl or RCuAl compounds was proposed. Nevertheless, the magnetization curves of the ErNi_0.2Cu_0.8Al compound (within the critical concentration region) showed behaviour close to the parent ErCuAl, which was confirmed as a ferromagnet. Neutron diffraction on ErNi_0.2Cu_0.8Al compound with applied magnetic field signifies appearing of the ferromagnetic order at the lowest applied magnetic field of 0.1 T. The magnitude of the ordered magnetic moment increases with increasing magnetic field in agreement with the magnetization curve, confirming tendency to ferromagnetic ordering or short-range magnetic order of ferromagnetic character in this critical region.

[en] We present results of a bulk-properties study on the DyNiAl single crystal. DyNiAl orders magnetically below T_C=30 K and undergoes further magnetic phase transition at T₁=15 K. The Dy-moments are aligned ferromagnetically along the hexagonal c-axis between T_C and T₁. Additional antiferromagnetic component develops below T₁ that leads to a canted magnetic structure at low temperatures. Magnetization data indicate uniaxial magnetic anisotropy with anisotropy field of 25 T and considerable intra-basal-plane anisotropy

[en] The ErNi_1-xCu_xAl compounds have been studied from the view of crystallographic structure and magnetic properties by means of X-ray and neutron diffraction, magnetization and heat capacity measurements. The hexagonal ZrNiAl-type crystal structure adopted by the parent compounds ErNiAl and ErCuAl is conserved over the entire composition range. The concentration dependence of lattice parameters shows a discontinuity between x=0.5 and 0.6 both in paramagnetic and magnetically ordered phase. The evolution of magnetism from antiferromagnetism (AF) with Er-moments within the basal plane in ErNiAl to the simple ferromagnetism (F) with moments along the c-axis in ErCuAl is rather complex. The AF ordering is characterized by a propagation vector (1/2),0,(1/2) with moments within the basal plane in the low Cu-concentration region for x up to 0.40. An incommensurate component with Er-moments along c develops within the range of 0.20≤x≤0.40 and grows on account of the commensurate one. The ErNi_0.5Cu_0.5Al is a simple F with moments along c. For concentrations with x=0.6 and 0.8 signs of short-range ordering were revealed

[en] Highlights: • EuRu2P2 is a ferromagnet with a small anisotropy with a as an easy magnetization axis. • The magnetocrystalline anisotropy was confirmed by ab-initio calculations. • Full saturated magnetic moment confirms the Eu2 + state over all pressures. • Sudden drop of Tc at 1.5 GPa is ascribed to the lattice compressibility change. -- Abstract: The EuRu₂P₂ single crystal was investigated by means of magnetic, transport and thermodynamic studies at ambient and hydrostatic pressures. A small magnetocrystalline anisotropy with crystallographic [100] direction as an easy magnetization direction was found by experimental measurements and confirmed by first-principles calculations. We connect a previously reported change in the compressibility observed at room temperature to a rapid change of ordering temperature under applied hydrostatic pressure.

[en] We report on detailed low-temperature measurements of the magnetization, the specific heat and the electrical resistivity on high-quality CeRuSn single crystals. The compound orders antiferromagnetically at T_N = 2.8 K with the Ce³⁺ ions locked within the a–c plane of the monoclinic structure. Magnetization shows that below T_N CeRuSn undergoes a metamagnetic transition when applying a magnetic field of 1.5 and 0.8 T along the a- and c-axis, respectively. This transition manifests in a tremendous negative jump of ∼25% in the magnetoresistance. The value of the saturated magnetization along the easy magnetization direction (c-axis) and the magnetic entropy above T_N derived from specific heat data correspond to the scenario of only one third of the Ce ions in the compound being trivalent and carrying a stable Ce³⁺ magnetic moment, whereas the other two thirds of the Ce ions are in a nonmagnetic tetravalent and/or mixed valence state. This is consistent with the low-temperature CeRuSn crystal structure i.e., a superstructure consisting of three unit cells of the CeCoAl type piled up along the c-axis, and in which the Ce³⁺ ions are characterized by large distances from the Ru ligands while the Ce–Ru distances of the other Ce ions are much shorter causing a strong 4f-ligand hybridization and hence leading to tetravalent and/or mixed valence Ce ions. (paper)