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Magnetic multilayers of (Ir/Co/Pt)6 with interfacial Dzyaloshinskii-Moriya interaction (IDMI) were deposited by magnetron sputtering with Co thickness d=1.8 nm. Exploiting magneto-optical Kerr effect in longitudinal mode microscopy, magnetic force microscopy, and vibrating sample magnetometry, the magnetic field-driven evolution of domain structures and magnetization hysteresis loops have been studied. The existence of weak stripe domains structure was deduced – tens micrometers size domains with in-plane "core" magnetization modulated by hundred of nanometers domains with out-of-plane magnetization. Micromagnetic simulations interpreted such magnetization distribution. Quantitative evaluation of IDMI was carried out using Brillouin light scattering (BLS) spectroscopy as the difference between Stokes and anti-Stokes peak frequencies Δf. Due to the additive nature of IDMI, the asymmetric combination of Ir and Pt covers led to large values of effective IDMI energy density Deff. It was found that Stokes and anti-Stokes frequencies as well as Δf, measured as a function of in-plane applied magnetic field, show hysteresis. These results are explained under the consideration of the influence of IDMI on the dynamics of the in-plane magnetized "core" with weak stripe domains. [ABSTRACT FROM AUTHOR]

(Co/Au)N ultrathin multilayers with perpendicular and in-plane magnetic anisotropy were studied experimentally using a combination of ferromagnetic resonance, magneto-optical magnetometry and microscopy (with both in-plane and out-of-plane magnetization-sensitive longitudinal and polar Kerr effects), and magnetic force microscopy (MFM). Three-dimensional magnetization distributions were reconstructed from micromagnetic simulations complemented by the measured magnetic parameters of the multilayers and observations by Kerr microscopy and MFM. It is shown that, in the reorientation phase transition (RPT) zone - the range of anisotropy characterized by 0 < Q < 1 (the ratio of the anisotropy energy to be gained by magnetization along the easy axis perpendicular to the sample surface, and the magnetostatic energy of a uniformly magnetized layer along the surface normal) - the three-dimensional magnetization distributions consist of alternating pairs of vortices and half-antivortices, both with in-plane magnetized cores and elliptical cross-sections. It is shown that an increase in N leads to a significant increase in the saturation field as well as changes in the hysteresis loop shape, domain structure size, and geometry. We demonstrate by simulations and prove by experimentation that, in multilayers with Q < 1, an increase in N induces the nucleation of out-of-plane magnetized domains, which then triggers magnetostatic interlayer coupling and RPT onset to out-of-plane magnetization states. We report on the observations of large micrometer-sized metastable domains (connected with the vortex cores) with the in-plane magnetization modulated by submicrometer-sized out-of-plane domains with sizes defined mainly by magnetostatics. [ABSTRACT FROM AUTHOR]

Amorphous yttrium iron garnet films ranging in thickness from 100 to 600 nm have been produced on single-crystal silicon substrates by sputtering a polycrystalline target with the composition YFeO (yttrium iron garnet) by a mixture of argon and oxygen ions. Before film growth, AlO or SiO buffer layers up to 0.8 μm in thickness were grown on the Si surface. The heterostructures were crystallized by annealing in air at a temperature of 950°C for 30 min. The properties of the films were studied by magneto-optical techniques, using Kerr effect and ferromagnetic resonance measurements. The Gilbert damping parameter reached 2.8 × 10 and the effective planar magnetic anisotropy field was independent of the nature of the buffer layer. This suggests that the thin-film heterostructures obtained in this study are potentially attractive for use in spin-wave semiconductor devices. [ABSTRACT FROM AUTHOR]

Ultrathin Co films were grown on vicinal Si(III) substrate with Cu buffer layers. Room temperature ferromagnetic behaviour of Co layer thicker than 4 monolayers was confirmed by the magneto-optical Kerr effect. Ferromagnetic resonance measurements have proven the coexistence of the magnetocrystalline anisotropy along with the growth- and vicinal induced uniaxial out-of-plane and in-plane contributions. Multi-jump hysteresis loops were observed for selected in-plane orientations of magnetic field which is explained by the competition of different anisotropy contributions. [ABSTRACT FROM AUTHOR]

In the present work we report on magnetization reversal process, anisotropy and domain structures in ultrathin Au/Co(0001)/Au films deposited on vicinal Si(111) substrates. The measurements were performed using a magneto-optical Kerr effect based magnetometer, a polarizing optical microscope and a ferromagnetic resonance spectrometer. Co thickness induced spin-reorientation from out-of-plane into in-plane magnetization was studied. Changes of in-plane magnetic anisotropy symmetry were deduced from shapes of magneto-optical hysteresis loops and from analysis of angular dependences of the resonance field. The experimental data have been discussed taking into account both uniaxial out-of-plane anisotropy and step-induced uniaxial in-plane anisotropy. A preferential orientation of domain walls in 3ML thick Co films was observed. The finding is explained by the step-induced magnetic anisotropy. [ABSTRACT FROM AUTHOR]

The magnetic anisotropy of ultra-thin Au/Co/Au magnetic films epitaxially grown on vicinal monocrystalline (11-20) sapphire substrates with different miscut angles, covered with a Mo buffer, are investigated by means of ferromagnetic resonance and magnetooptical techniques. Changes in in-plane magnetic anisotropy symmetry were deduced from the shape analysis of magnetization curves and the angular dependence of the resonance field measured in the sample plane. Two-fold and four-fold symmetry was observed for different miscut angles. The preference of the domain wall orientation was observed. The experimental data are discussed taking into account the shape anisotropy, perpendicular uniaxial anisotropy, and step-induced uniaxial anisotropy. [ABSTRACT FROM AUTHOR]