[en] Joule heating technique was used to anneal Fe₇₃Al₅Ga₂P₁₁C₅B₄ alloys. Magnetic properties as function of current density were characterised by hysteresis loops. Time and temperature dependence of the resistivity and temperature dependence of the susceptibility were measured in order to study the crystallisation behaviour. The results indicate a nearly linear dependence of the onset of the crystallisation of this sample on the heating rate

No abstract available

[en] The effect of the addition of Nb in Fe-Si alloys was investigated by measuring the magnetic properties and investigating the microstructure. Nb enhances (about 10 times) the coercivity and changes the microstructure as well as the temperature dependence of the coercivity. There exists indication that Nb enters in the lattice

[en] The effect of Joule heating on the magnetic properties and microstructure was investigated in Fe₇₃Al₅Ga₂P_11-xC₅B₄Si_x (x=1, 3) ribbons with a thickness of about 40 μm. It turns out that, in these alloys, the coercive field, the pinning field and the time dependence of the initial permeability decrease with increasing current density applied during a thermal treatment via Joule heating up to the occurrence of crystallization. At the as-cast state, the sample with x=3 exhibits better soft magnetic properties than those of the sample with x=1; however, after an optimum annealing, both alloys present similar magnetic properties. The temperature dependence of the resistivity shows clear two stages crystallization process for the Fe₇₃Al₅Ga₂P₈C₅B₄Si₃ alloy. The microstructural and magnetic inhomogeneities of the annealed Fe₇₃Al₅Ga₂P₈C₅B₄Si₃ alloy with lowest coercivity were investigated by means of a small-angle neutron scattering method. The improvement of the soft magnetic properties caused by Joule heating of materials is due to the internal stress relieve originated during the production of the ribbon and to the enlargement of the domain wall thickness, consequently the reduction of the anisotropy

[en] Austromag offers high magnetic fields for various applications in solid state physics. The quasistatic high field facility gets the power (10 MWs) from the line of the city, reaching 40T in a long pulse (up to 1s). Additionally exist various short pulse facilities (pulse duration between 10 and 100 ms) which are energized by a condensor battery. New types of high field magnets (foil coil) were developed. Measurements are possible between 4.2 K and 800 K. The main experiments are: magnetization, magnetoresistence, anisotropy and magnetostriction. New measuring techniques were developed such as pressure dependence of anisotropy and magneto-electric coefficient

[en] GdCo_9-xSi_4+x (x = -0.2 to x = 0.2) and TbCo₉Si₄ exhibit the tetragonal LaFe₉Si₄ structure (space group I4/mcm). Magnetically these samples are ferrimagnetic with ordering temperatures close to 50K. The ferrimagnetic magnetization is found to decrease with decreasing Si content, thus, revealing an increasing cobalt sublattice magnetisation. The antiparallel coupling of the Gd- and Co-sublattice magnetisations breaks up at lower critical fields H_l well above 20 T. From the lower critical field H_l as well as from the slope ΔM/ΔH for fields above H_lthe inter-sublattice molecular coefficient can be determined which is approximately constant within this solid solution

[en] Several sets of steel samples, like cold-rolled low carbon steel with different rolling reductions and thermal aged Fe-1 wt% Cu alloys, are investigated with respect to magnetic parameters such as coercivity, remanence and shape of the hysteresis loop. Measurements are performed in a magnetic open system, which allows magnetic saturation of the material and in a magnetic closed system using ring or picture frame shaped samples. The results obtained for ring or picture frame shaped samples give a much better accuracy for determining the coercivity. The coercivity (remanence) of the cold-rolled carbon steel samples increases (decreases) systematically with the rolling reduction. The duration of the thermally aging procedure performed at 450 deg. C has nearly no influence on the coercivity value. However, if thermally aging is applied on a cold-rolled sample, the coercitivity decreases with increasing aging time

[en] Measuring techniques for studying the magnetoelectric (ME) effect are not established yet. In this work, we report about a lock-in technique for studying the ME effect in ME-multiferroic composites. The philosophy as well as the theory of measurement is discussed. The advantages and disadvantages of this method are described. Details on our experimental set-up in which an AC field with frequencies ranging from 1 to 10 kHz and amplitudes from 1 to 20 Oe are superimposed onto a DC bias field up to 15 kOe are shown. Treatments of the zero-signal and operation modes are demonstrated. ME investigations on CoFe₂O₄-BaTiO₃ composites are discussed in details

[en] We investigated the structural and magnetic properties of the as-cast Fe_100-(x+y)Si _x Nb _y (with 9.5x20 and 0.5y12) and Fe_78.5Si₂₀Ta_1.5 alloys by means of coercivity measurements and zero-field nuclear magnetic resonance (NMR) technique. The NMR spectra of these alloys present broad resonance lines at around 80 and 130 MHz. An increase in the local magnetic stiffness with increasing Nb content was found. These results are discussed based on previously reported results about the microstructure of the same specimen and coercivity measurements

[en] The phase relations of the GdCo_13-xSi_x system have been studied by means of scanning microscopy, microprobe analysis and x-ray diffraction. Single-phase samples GdCo₉±_δSi₄±δ (structure type LaFe₉Si₄ with space group I4/mcm) are formed in a narrow composition range vertical bar δ vertical bar ≤0.2, where GdCo₉Si₄ forms as a fully ordered ternary compound. The magnetic properties of GdCo₉Si₄ have been investigated by ac susceptibility, magnetization, specific heat and resistivity measurements. These experiments reveal ferrimagnetism below about 47 K, which is analysed in terms of a two-sublattice molecular field model with a local moment Gd subsystem coupling antiparallel to the itinerant ferromagnetic Co 3d sublattice. The 3d-3d exchange of the latter is the driving force for the onset of long range magnetic order. The validity of the two-sublattice model is demonstrated by high field measurements, showing that the ferrimagnetic coupling starts to break up at a lower critical field μ₀H_l ∼ 27T. The magnetic ground state of GdCo₉Si₄ has been analysed on a microscopic basis via LSDA electronic structure calculations