The effect of texture, dispersion, and interaction on transverse susceptibility has been studied. We have developed a model based on the well-known Stoner-Wohlfarth model, by taking into account the texture, the anisotropy field value distribution, and the intergranular magnetic interactions. This model shows a good agreement with experimental measurements on granular FeCoV thin films and allows us to determine the mean value of the local magnetic anisotropy, intergrain interaction, and texture of these alloys.

Structural and magnetic properties of planar nanowire arrays of Co grown on oxidized vicinal silicon (111) A detailed study of the structure and magnetic properties of V / Co versus Co/ V bilayers grown on MgO͑001͒ substrates with cubic and hexagonal Co crystal structures is presented. Co is found to adopt fcc structure when grown on MgO͑001͒, while it adopts hcp structure when grown on V͑001͒. The different magnetocrystalline anisotropy associated with each structure gives rise to different magnetic properties for the otherwise equivalent symmetric Co-V bilayers.

The morphological and magnetic properties of Co nanoparticles deposited by triode sputtering on Si 3 N 4 at 550°C are reported. The nominal thickness of Co ranges from 2 up to 15 nm, and two different capping layers, Au and Pt, are used. The nanoparticles were characterized by x-ray diffraction and atomic force microscopy. Morphological and structural studies show that the nanoparticles grow in a well-defined nanostructured pattern and adopt a hexagonal closed packed crystalline structure. Moreover, the average particle size and the particle size dispersion increase as the thickness increases, due to percolation. Experimental characterization of effective anisotropy field was carried out with transverse susceptibility. Transverse susceptibility measurements reveal an in-plane isotropic magnetic behavior. Both the effective anisotropy field and the coercive field increase as the particle size increases, following a D 6 dependence, which is typical for three-dimensional structures in the framework of the random anisotropy model. The relationship between the particle size distribution and the anisotropy field distribution is shown, explaining the significant dependence of the magnetic behavior on the Co layer thickness. On the other hand, different capping layers give rise to a change in the magnetic response due to the modification of the interparticle interaction.

Co thin films have been deposited by sputtering on glass substrates. The film thickness ranges from 10 to 170 nm. Structural results show that the films are polycrystalline with a dominant hcp structure. An ultrafine distribution of crystallites with diameters about 5 nm is found for the thinnest samples, which is also detected by a smooth surface. The grain size grows as the thickness increases in consequence an evolution occurs from a well-defined uniaxial anisotropy to a more isotropic behavior. This gives rise to an increase in the coercivity, domain wall pinning strength, and its dispersion. The magnetization reversal mechanism is also influenced by the film thickness. Using transverse susceptibility measurements we have found that the maximum domain wall pinning strength increases significantly as the film thickness increases.Index Terms-Co thin film, magnetic anisotropy, magnetization reversal, transverse susceptibility.

Articles you may be interested inImproving soft magnetic properties of nanometer CoNbZr films in gigahertz frequency range by electrical pulse annealing J. Appl. Phys. 113, 17A341 (2013); 10.1063/1.4800744 Microfluxgate sensor with amorphous cobalt (Co-Nb-Zr) soft magnetic core for electronic compass J. Appl. Phys. 99, 08M306 (2006); 10.1063/1.2172540 Magnetoresistance and performance of amorphous-Co Nb Zr ∕ Co ∕ Cu ∕ Co magnetic multilayers J. Appl. Phys. 99, 08T105 (2006); 10.1063/1.2171019 ( FeCo/Co-M ) n soft magnetic multilayers with uniaxial anisotropy and very high saturation magnetization J. Appl. Phys. 93, 5498 (2003); 10.1063/1.1563824 Effect of Ti, V, Cr, and Mn additions on the magnetic properties of a nanocrystalline soft magnetic Fe-Zr-B alloy with high magnetic flux densityExperimental characterization of macroscopic effective anisotropy field and coercive field for nanocrystalline ͑FeCoV/ CoNbZr͒ 16 multilayers was carried out with transverse susceptibility. The multilayer structure consisting of a FeCoV ferromagnetic nanogranular layer covered with a CoNbZr amorphous layer was prepared by rf sputtering. All multilayers had the same thickness of CoNbZr ͑3 nm͒ with FeCoV layer thickness varying between 6 and 30 nm. The properties of the optimized multilayer structured films are related to an appropriate grain size of FeCoV where the CoNbZr layer acts as a very effective grain refiner and reduces the average grain size. The experimental values of the coercive force and the macroscopic uniaxial anisotropy were related to the grain size. The values were analyzed according to a two dimensional random anisotropy model which takes into account the uniaxial anisotropy.