Dispersion relations for the spin-motion angles in spin-polarized electron reflectionDispersion relations for the spin-motion angles in spin-polarized electron reflection

International audienc

Structural, electrical and magnetic properties of evaporated permalloy thin films: effect of substrate and thickness

We have studied the effects of the substrate and the thickness on the structural, electrical and magnetic properties of permalloy thin films Ni81Fe19 (Py). Series of Py thin films were evaporated on four various substrates: glass, kapton, Si(1 0 0) and Si(1 1 1). The thickness ranges from 13 nm to 190 nm. We show that evaporated permalloy on kapton and Si(1 1 1) present a strong ⟨1 1 1⟩ preferred orientation for samples thicker than 85 nm; however, the films grown on glass and Si(1 0 0) present a weak (1 1 1) texture for most of these samples. Generally, the lattice constant for Py/glass, Py/Si(1 0 0) and Py/Si(1 1 1) samples is found to be smaller than the bulk value (abulk), while for the Py/kapton, it is larger than abulk. There is an overall increase of the grain sizes (100 Å–480 Å) with thickness for Py/Si(1 1 1), Py/Si(1 0 0) and Py/glass. For the Py/kapton samples, the grain sizes (about 130 Å) seem to be independent of the thickness. The resistivity, ρ, decreases with increasing thickness for all samples. The highest values of ρ were observed in the Py/kapton thin films, diffusion at the grain boundaries might be in part responsible for these high values. The magnetization easy axis is found to be in the film plane for all samples. For all series, the two thinner films seem to exhibit a perpendicular magnetocrystalline anisotropy. The coercive field, HC//, values range from 1 Oe to 67 Oe. A peak in the HC// vs. t curve is observed for Py/Si while for Py on glass and Py/kapton, HC// seems to be constant. We also observed that for the thicker Py/Si(1 1 1) samples, the coercivity decreases as the grain sizes increase

Enhancement of longitudinal Kerr rotation in Fe/Al

We present experimental results on longitudinal magneto-optic Kerr effect in composite systems based on thin Fe layers associated with amorphous alumina (Al2O3). [Al2O3/Fe]m-samples ($m=1,\,2$) have been prepared by rf magnetron sputtering onto Si(100) substrate. We have investigated the effect of the Al2O3 and Fe thicknesses on the Kerr rotation. The geometry of the multilayers is predicted theoretically by using deduced experimental magneto-optical constants. It will be shown how large Kerr rotation values can be obtained by adjusting sample parameters. For instance, a Kerr rotation close to 7° has been observed from an Al2O3/Fe/Al2O3/Fe/Si multilayer. The reflectivity and the figure of merit are discussed as a function of the Al2O3 thickness

Structural, electrical and magnetic properties of evaporated Ni/Cu and Ni/glass thin films

International audienc