Magnetic anisotropy and magnetoelastic properties of Fe10Ni90 films

This work is devoted to studying the effect of the thickness and type of the buffer sublayer on the magnetic anisotropy and the magnetoelastic properties of Fe10Ni90 films. It is established that the anisotropy of Fe films strongly depends on thickness, which can be associated with the influence of several mechanisms of anisotropy formation. Measurements of the magnetostriction of thin films using magnetoresistive curves were made. The value of the magnetostriction constant also depends on the thickness of the films. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-72-10044This work was financially supported by the Russian Science Foundation (RSF), project No. 18-72-10044

Magnetic properties of GdCo-Al2O3 composite films

The purpose of this work was to synthesize and study magnetic properties of composite films consisting of Gd-Co ferrimagnetic system and Al2O3 dielectric matrix. GdCo-Al2O3 films of different composition were synthesized by magnetron co-sputtering of Gd, Co, and Al2O3 targets in an Ar atmosphere. Investigation of magnetic properties was carried out using a vibrating sample magnetometer in the temperature range from 10 to 300 K. The obtained results showed that in the composite system with a volume of dielectric material exceeding 50% a superparamagnetic state is realized, indicating granular microstructure. In this case, the granules show signs of ferrimagnetic ordering. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-72-10044This work was financially supported by the Russian Science Foundation in the framework of research project No. 18-72-10044

Effect of temperature on the exchange bias in FeMn/X/Fe20Ni80 (X = Ta, Gd) films

The influence of temperature on the exchange bias in the Fe50Mn50/X/Fe20Ni80 (X = Ta, Gd) films was investigated. It is shown that in the film structures without a spacer between FeMn and permalloy layers, the temperature dependence of the value of the exchange bias field is non-monotonous. The introduction of an ultrathin spacer leads not only to a change in the magnitude of the interlayer exchange coupling, but also to a change in the behavior of its temperature dependence. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-72-10044The research work has been financially supported by the RSF grant, project no. 18-72-10044. The authors would also like to thank M.E. Moskalev for obtaining X-ray diffraction pattern of the film samples

Co/Cu/Co pseudo spin-valve system prepared by magnetron sputtering with different argon pressure

Thin Co films were fabricated by DC magnetron sputtering. The effect of argon pressure on the microstructure, surface morphology and magnetic properties of the samples was systematically studied. It was found that with the increase of argon pressure, the sharpness of the crystalline texture of the samples declines, the roughness of film surfaces and the coercivity of the films increase. Based on these results, a Co/Cu/Co pseudo spin-valve system was designed and the corresponding structures were fabricated. The difference in coercivity of magnetic layers was obtained by deposition of the Co layers at different Ar pressures. Change of the resistance of this trilayer is induced at a moderate field by the spin rotation in the soft layer with lower coercivity. © 2015 Trans Tech Publications, Switzerland

Micromagnetic modelling of stripe domains in thin films with a columnar microstructure

A micromagnetic model of thin films with columnar microstructure in the form of a matrix with reduced magnetic properties and embedded columns with high aspect ratio is presented. Such microstructure is typical for some films based on rare-earth and 3d transition metal alloys, in particular for La-Co films, that were chosen as an object for our modelling. Described structural features promote an effective perpendicular magnetic anisotropy that for thick enough films leads to formation of the stripe domain pattern. Our work addresses to the problem of finding equilibrium characteristics of stripe domains for the case of infinite columnar films. Herein it is shown how width of stripe domains, remanent magnetization and energies depend on number of replicas of periodic boundary conditions and the size of modelling volume. Equilibrium values of listed quantities can be found by extrapolating obtained dependencies. © 2021 Author(s).This work was supported by Russian Science Foundation, project No. 19-72-00141

Negative anisotropy in Fe10Ni90 films

It is shown that in the Fe10Ni90 film the easy magnetization axis can be formed not along the deposition field, as it occurs in the Fe19Ni81 film, but across, that is a "negative anisotropy" effect occurs. A model that qualitatively describes this effect is proposed. Using the Kerr magnetometer, local measurements of the variation of the direction of the easy magnetization axis over the area of the film sample Fe10Ni90 were carried out and compared with the general view of the domain structure. © Published under licence by IOP Publishing Ltd