Z. M. Stadnik

The Influence of Quenching Rate on the Magnetic-Properties of Microcrystalline Alloys Co80zr20-Xbx

Magnetic properties of melt‐spun Co80Zr20−xBx microcrystalline alloys (0≤x≤8) depend crucially on the quench rate.The optimized values of Hc =2.68 kOe and (BH)max =2.10 MGu2009Oe were obtained for Co80Zr16B4 melt‐spun with the substrate surface velocity of 48 m/s. A new crystalline phase of Co5Zr was observed.

Antiferromagnetism in 57Co-doped La2CuO4-y studied by Mossbauer spectroscopy

Mössbauer effect studies of57Co-doped La2CuO4−y were performed at temperatures between 4.2 K and room temperature. These confirm the antiferromagnetic ordering of these compounds below room temperature. Temperature dependence of the quadrupole splitting shows that the hyperfine field is at an angle with thec-axis.

Properties of as-quenched and hydrogenated CuFeTi alloys☆

Abstract X-ray diffraction, differential thermal analysis and Mossbauer effect measurements have been used to study the properties of amorphous Cu 100-x-y Fe x Ti y alloys in the as-quenched state after hydrogenation and after various heat treatments.

Local magnetic moments in crystalline and amorphous alloys

Recent57Fe and61Ni Mössbauer spectroscopy studies of Fe and Ni magnetic moments in crystalline and amorphous alloys, as well as X-ray photoelectron spectroscopy experiments related to Fe magnetic moments, are reviewed. It is shown that in Fe-Ni-M (M=metalloids or Zr) amorphous alloys, Ni atoms do carry a magnetic moment, similarly to crystalline Fe-Ni alloys, and that literature data indicate that amorphous iron could be polymorphic, with low- and highmoment forms. It is demonstrated that the Fe 3s multiplet splitting in the X-ray photoelectron spectra of metallic crystalline and amorphous alloys is not a reliable measure of Fe magnetic moments.

Electrical resistivity of FeCr- and NiCr-based amorphous alloys

Abstract We have measured the resistivity of amorphous Fe 80 − x Cr x B 12 Si 8 and Ni 80 − x Cr x B 12 Si 8 as function of temperature in the temperature range of 4.2 to 300 K. Although the absolute change in the resistivity is small, adding chromium to the base alloys results in large changes in the temperature dependence of the resistivity in these alloys. This temperature dependence is markedly different for these two alloy systems, with the largest changes measured for the Niue5f8Crue5f8M (M ≡ metalloid) glasses. The results are explained qualitatively using existing theoretical models.

61Ni Mössbauer study of the surface hyperfine magnetic field in nickel

Abstract61Ni Mössbauer measurements have been performed at 4.2 K on spherical Ni particles with an average diameter of 100 and 30 Å, covered with a protective layer of SiO. Their spectra contain a surface component with a significantly reduced hyperfine magnetic field as compared with the field in the bulk. This result confirms recent theoretical predictions.

An57Fe Mössbauer effect study of the highT c superconductor GdBa2Cu3O7−y

Split source57Fe Mössbauer effect spectroscopy has been performed between 4 K and 295 K on the superconducting perovskite GdBa2Cu3O7−y. No evidence is seen for magnetic splitting at low temperatures as reported in some split absorder57Fe Mössbauer experiments on this material. There is evidence for phonon mode softening, as observed for119Sn Mössbauer spectra of some other highTc superconductors.

Nickel contribution to the magnetism of the Ni-Fe-V alloy

Abstract 61Ni Mossbauer effect measurements have been performed on (Ni0.594Fe0.406)0.841V0.159 alloy and Ni metal at 4.2 K. The hyperfine magnetic field at 61Ni nuclei, Hhf, in the alloy exhibits a distribution characterized by the average value H hf = 74.6(3.4) kOe and the second moment ≡M2 = 16.1(3.1) kOe. The non-zero value of Hhf in the alloys is shown to imply the existence of the magnetic moment at Ni atoms, which is at variance with the environment effect model.

ON MANY-ELECTRON EFFECTS AND MULTIPLET SPLITTINGS IN X-RAY PHOTOELECTRON-SPECTROSCOPY AS A DIAGNOSTIC-TOOL FOR METALLIC GLASSES

Abstract (Ni1−xFex)77Si10B13 glasses and crystalline iron, nickel, Fe2Gd and Fe2Ti were studied with X-ray photoelectron spectroscopy. It is shown that characteristics of Ni 2p 3 2 satellites are sensitive to changes in the glass composition. It is found that the Fe 3s multiplet splitting, both in glasses and crystalline alloys, does not scale with the iron magnetic moment.

Nickel magnetic moment in (Ni 1-x Fe x ) 77 Si 10 B 13 glasses

(Ni 1-x Fe x ) 77 Si 10 B 13 metallic alloys with x = 0.0, 0.1 and 0.9 have been studied at 4.2 K with61Ni Mossbauer spectroscopy. It is shown that Ni atoms bear no magnetic moment in Ni 77 Si 10 B 13 , and that their moment in (Ni 0.9 Fe 0.1 ) 77 Si 10 B 13 and (Ni 0.1 Fe 0.9 ) 77 Si 10 B 13 is respectively 0.38 and 0.65 μ B . An analysis based on our and literature data shows that, similarly to Ni-Fe crystalline alloys, Ni atoms do carry a magnetic moment in Ni-Fe-based amorphous alloys.