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Cylindrical soft magnetic Co films, nanostructured with a grain size of 1-2 nm and between ≈1.3 and 90 nm in thickness, were produced by the pulsed laser deposition technique. These films showed a magnetostrictive property. The magnetoelastic inverse Wiedemann effect, or IWE, of longitudinal magnetization as a function of the circular applied magnetic field, M z -H φ , was measured. The IWE made it possible to explain the magnetization processes according to an initial reversible rotation of the magnetization followed by magnetic wall nucleation and propagation. A magnetization rotation model allowed us to compare the reversible part and the first irreversible magnetization processes corresponding to the IWE. In this way, the values of the helical magnetic anisotropy, K h , due to the helical stresses, σ h , generated by an applied torque to the films, were determined. A linear increase of the nucleating magnetic wall field, H N , with the applied torque, or with σ h , was observed. In addition, the IWE made it possible to establish the non-dependence of the saturation magnetostriction constant, λ s , on the sample thickness and to determine the value of this negative isotropic λ s ≈ −4.8 × 10 −6 .

Planar and cylindrical Co thin films have been obtained by pulsed laser ablation. X-ray diffractograms have shown no crystalline structure for the as-deposited samples, while the 450 °C annealed samples exhibit Co fcc crystalline peaks. The Scanning Tunnelling Microscopy has revealed a small increase of the surface roughness for the annealed films. The Hall effect has been used to determine the value of the spontaneous magnetization, Ms, at room temperature; Ms, = 14 kgauss for the as-deposited sample and Ms, = 17.6 kgauss for the 450 °C annealed sample. From transverse magnetooptic Kerr effect, it has been found that the as-deposited samples exhibit magnetic bistability, with a coercive field, Hc, = 6 0e. The annealed samples also show a bistable behavior until the annealing temperature is 450 °C. Besides, it has been observed an increase of Hc up to = 50 Oe, when the annealing temperature increases. The vibrating sample magnetometry has confirmed these results, showing that the magnetization participating in the magnetooptic effect for these low fields is the total spontaneous magnetization of these samples. Moreover, the cylindrical films exhibit magnetoelastic behavior when they are subjected to angular deformation. It has been found that the saturation magnetostriction constant is negative.

The magnetic domain configurations of soft magnetic, nanostructured, pulsed laser-deposited Co films were investigated. Their dependence on both the thickness t (20 nm ≤ t ≤ 200 nm) and the anisotropy was studied. Charged zigzag walls, with a characteristic saw-tooth vertex angle θ, were observed. θ changed with t from θ ≈ 17° to ≈25°, presenting an intermediate sharp maximum that has not been described before. The reduced length of the zigzag walls also exhibited a peak at t ≈ 70 nm. The relationship between the total reduced length and the density energy of the magnetic wall allowed us to establish a change from a Néel-type to a Bloch-type core of the zigzag walls at this thickness, t ≈ 70 nm. We also accounted for the magnetic energy arising from the surface roughness of the thinner films after imaging the film surface morphologies. Moreover, this distinctive behaviour of the zigzag walls of these low-anisotropy films was compared to that of high-anisotropy films.

Soft magnetic Co and Fe films were deposited by pulsed laser ablation on Cu wires. The circular magnetic susceptibility of the cylindrical films was measured by applying an ac circular magnetic field at frequencies up to 6GHz. The measured ferromagnetic resonance frequency of the Co films was 2.5GHz, and the real part of the magnetic susceptibility at the lowest frequency of our measurements was 150. These results were explained as solutions of the Landau-Lifshitz-Gilbert equation, taking into account that the easy magnetization direction of the Co films was along the wire axis. Further measurements with an axial external magnetic field were consistent with this view. In contrast, for the Fe films, significant values of the circular magnetic susceptibility were measured only in the presence of external magnetic fields applied along the wire axis. This result indicated that the easy magnetization direction of the Fe films was not along the Cu wire axis. The magnetic anisotropy of both Co and Fe cylindrical films might originate from magnetoelastic effects, resulted from built-in stress. The different behaviors of the Co and Fe cylindrical films would then be attributable to the different signs of their magnetostriction constants λs.

Amorphous soft magnetic CoP electrolytic multilayers have been obtained with a controlled surface magnetic anisotropy. The surface magnetization easy direction can be continuously altered from an initial perpendicular position to a final arrangement within the longitudinal plane. This continuous change of magnetization direction is controlled during the sample production stage and, therefore, there is no need to subject the films to subsequent treatments such as, for example, thermal, stress, or magnetic field annealing. The magnetic domain configurations, as observed by means of the Bitter technique, have revealed a continuous variation from an initial stripe domain structure to a final situation in which the magnetization lies within the plane of the films and magnetic domain walls are observed. The magneto-optic behavior of these multilayers has also revealed this continuous evolution from an initial perpendicular easy direction for the magnetization to a configuration in which the surface magnetization has a planar longitudinal direction. The surface magnetization processes are hence modified from the initial rotation magnetization to final processes corresponding to magnetic wall displacements. Control of magneto-optic behavior can be of interest for technical applications, given there would be no need for sense windings. A phenomenological discussion about the evolution of the surface magnetization easy direction is also presented.