Magnetootpor u ternarnim staklastim slitinama Zr2(Ni1-xMx)1

We have measured magnetoresistivity of some ternary glassy Zr2(Ni1-xMx)1 alloys, M = Ti,V,Co and Cu, in magnetic fields up to 1.2 T at temperatures 4.2 K, 5 K, 6 K and 7 K. The magnetoresistivity of these alloys can be explained by adding contribution of the superconducting fluctuations to the contributions due to quantum coherence effects. The estimated values for inelastic relaxation times ti are very reasonable.Mjeren je magnetootpor nekih ternarnih staklastih slitina Zr2(Ni1-xMx)1, gdje je M = Ti, V, Co ili Cu, u magnetskom polju koje se mijenjalo od 0 T do 1.2 T, na temperaturama 4.2 K, 5 K, 6 K i 7 K. Pokazali smo da se magnetootpor tih slitina može objasniti dodavanjem doprinosa supravodljivih fluktuacija doprinosima koji nastaju uslijed kvantnih koherentnih efekata. Dobivene vrijednosti neelastičnih vremena raspršenja vrlo su prihvatljive

Višenamjenski mjerni udređaj zasnovan na AC susceptometru

The measuring device based on an AC susceptometer is described and some advantages of particular design are given. The measurements of resistance and hysteresis with the device are described. Some results of AC susceptibility, resistance and hysteresis measurement are shown.Opisujemo mjerni uređaj zasnovan na AC susceptometru i prednosti njegove izvedbe. Opisujemo metode mjerenja otpora i histereze tim uređajem. Prikazujemo ishode nekih mjerenja AC susceptibilnosti, otpora i histereze

Influence of the successive annealing on the magnetization processes in Fe_73.5Cu_1Nb_3Si_15.5B_7 ribbon

The model for the influence of core-current generated field Hp on the magnetization processes in ferromagnetic ribbons has been employed for the detailed analysis of the M-H loops and the corresponding dM/dt vs. H curves for Fe_73.5Cu_1Nb_3Si_15.5B_7 alloy, successively annealed at different temperatures

Magnetska svojstva Zr-3d staklastih slitina

Systematic analysis of the magnetic susceptibilities for a number of Zr-M glassy alloys (M = Cu, Ni, Co and Fe) and for ternary Zr2(Ni1−xMx)1 glassy alloys with M = Ti, V, Cr, Mn, Fe, Co and Cu has been performed. By combining our data for the magnetic susceptibility and superconducting transition temperature with the literature data for low-temperature specific heat, we have extracted the Pauli susceptibilities (χp) and the Stoner enhancement factors (S) for these alloys. The binary Zr-Cu and Zr-Ni alloys have practically the same S, whereas Zr-Co and ZrFe alloys show larger S which increases in going from Co to Fe. In ternary alloys, χp and S show pronounced maxima centred around M = Mn. For these alloys we also estimated S from the low-temperature magnetoresistivity.Napravili smo sustavnu analizu magnetske susceptibilnosti za niz Zr-M staklastih slitina (M = Cu, Ni, Co i Fe) i za ternarne Zr2(Ni1−xMx)1 staklaste slitine gdje je M = Ti, V, Cr, Mn, Fe, Co odnosno Cu. Kombinirajući naše podatke za magnetsku susceptibilnost i temperaturu supravodljivog prijelaza s podacima iz literature za specifični toplinski kapacitet na niskim temperaturama, izračunali smo Paulijevu susceptibilnost (χp) i Stonerov faktor (S) za naše slitine. Binarne Zr-Cu i ZrNi slitine imaju gotovo jednak S, dok Zr-Co i Zr-Fe slitine pokazuju veći S koji raste od Co prema Fe. U ternarnim slitinama, χp i S pokazuju izrazit maksimum centriran oko M = Mn. Za ove slitine izračunali smo S iz magnetootpora na niskim temperaturama

Utjecaj uzastopnog napuštanja na procese magnetiziranja Fe73.5Cu1Nb3Si15.5B7 vrpce

The model for the influence of core–current generated field Hp on the magnetization processes in ferromagnetic ribbons has been employed for the detailed analysis of the M − H loops and the corresponding dM/dt vs. H curves for Fe73.5Cu1Nb3Si15.5B7 alloy, successively annealed at different temperatures Ta ≤ 540 ◦C. The analysis shows that in the amorphous state (Ta ≤ 300 ◦C), only fraction of the main (inner) domain structure participates in the process of magnetization. Further annealing strongly reduces the local anisotropy and the average pinning strength of the domain walls , which results in a very low coercive field Hc for 400 ◦C ≤ Ta ≤ 500 ◦C. Simultaneously, the maximum magnetization Mm becomes almost equal to the saturation magnetization Ms (≈ 1.3 T) already in low magnetizing field (H0 = 100 A/m). The minimum of Hc (Ta = 450 ◦C) is associated with the formation of nanocrystalline Fe3Si grains, and high Mm and maximum permeability µmax and a low angle (between domain magnetizations and the ribbon axis) show that a whole domain structure is very simple in this range of Ta. Further annealing (Ta > 500 ◦C) increases and (which increases Hc) and reduces drastically µmax which is consistent with the earlier results for similar samples.Model za utjecaj polja Hp, generiranih strujom kroz uzorak, na procese magnetiziranja u feromagnetskim vrpcama iskorišten je za detaljne analize M − H krivulja i odgovarajućih ovisnosti dM/dt o H krivuljama uzastopno napuštane Fe73.5Cu1Nb3Si15.5B7 vrpce na različitim temperaturama (Ta ≤ 540 ◦C). Analize pokazuju da u amorfnom stanju (Ta ≤ 300 ◦C) samo dio glavne domenske strukture sudjeluje u procesu magnetiziranja. Napuštanjem na višim temperaturama naglo se smanjuje lokalna anizotropija i srednja jakost zapinjanja domenskih zidova . To rezultira vrlo niskim koercitivnim poljem Hc za 400 ◦C ≤ Ta ≤ 500 ◦C. Istovremeno, maksimalna magnetizacija Mm postaje približno jednaka magnetizaciji saturacije Ms (≈ 1.3 T) u niskom magnetizirajućem polju (H0 = 100 A/m). Minimum Hc (Ta = 450 ◦C) je povezan sa stvaranjem nanokristalnih Fe3Si zrna, a visoka Mm i maksimalna permeabilnost µmax te mali kut (između magnetizacija domena i osi vrpce) pokazuju da je cjelokupna domenska struktura vrlo jednostavna u tom području Ta. Napuštanje na višim temperaturama (Ta > 500 ◦C) izaziva porast i (zbog čega raste i Hc) te nagli pad µmax što je u skladu s drugim rezultatima za slične uzorke