Magnetic anisotropy in Ni/Fe and Fe/Cu/NiFe multilayers

Abstract

Multilayer samples of Ni/Fe and Fe/Cu/NiFe, fabricated by sputtering and characterized by transmission electron microscopy and electron diffraction, were studied by 57 Fe Mössbauer spectra and magnetization measurements. Mössbauer spectra taken in zero applied field at 300 K and 4.2 K showed midlayer and interface iron sites in Ni(20 Å)/Fe(x Å) samples with x = 20 Å, 30 Å, 50 Å, 80 Å and in-plane spin orientation. The reorientation of the magnetic moments at 4.2 K in increasing fields applied normal to the layers when combined with magnetization measurements enabled the magnetic anisotropy energy K of each sample to be evaluated. The trend of the values of K with iron layer thickness gave volume and interface anisotropy components K V = (−5 ± 1) × 10 4 J m −3 and K S = (−0.6 ± 0.4) × 10 −3 J m −2 where negative values indicate in-plane preference. Similar measurements on a series of samples of Fe(30 Å)/Cu(x Å)/Ni(80%)Fe(20%)(30 Å) with x = 10 Å, 20 Å, 30 Å, 50 Å showed a tendency toward increasing in-plane anisotropy energy K with decreasing thickness of the non-magnetic Cu layer.

Applied field Mössbauer study of shape anisotropy in Fe nanowire arrays

“…It was proved that Mössbauer spectroscopy is a powerful technique to investigate the magnetic anisotropy. [5][6][7] Previous zero-field Möss-bauer spectra of both Fe and FeCo nanowire arrays have the characteristics of disappearance of the second and fifth absorption peaks in the sextet, implying that the easy magnetization direction lies in the axes of nanowires. 8,9 However, the dependence of hyperfine fields and the intensities of the second and fifth lines on the applied field is not well known.…”

MAGNETIC AND ELECTRICAL PROPERTIES OF ELECTRON BEAM GUN DEPOSITED [Mn/Al] MULTILAYERED FILMS

“…Magnetic and electrical transport studies on magnetic multilayers have been of great interest in the recent years. Multilayers consisting of ferromagnetic metals and nonmagnetic metals were investigated for structure, magnetic and electrical studies [1][2][3][4][5][6]. The role of nonmagnetic spacer in tuning the interlayer exchange coupling (IEC) between two neighboring magnetic layers has been first reported by Grunberg [7.] Subsequently, giant magnetoresistance (GMR) and oscillations in IEC with varying width of the nonmagnetic spacer were discovered [8][9][10].…”