Search

We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on GaAs-based substrates and present results of the study of ferromagnetic resonance (FMR), spin wave propagation and interaction between spin excitations and 2D electrons in interface layer in YIG/AlOx/GaAs-heterostructures. It is found that the contribution of the relaxation process to the FMR linewidth is about 3.6%–6.6% of the linewidth . The main contribution to the FMR linewidth of sputtered YIG films is given by a magnetic profile inhomogeneity. Transistor structures with two-dimensional electron gas (2DEG) channels in AlOx/GaAs interface governed by YIG-film spin excitations are designed. An effective influence of spin excitations on the current flowing through the GaAs 2DEG channel is observed. It is found that the light illumination results in essential changes in the YIG-film FMR spectrum of transistor structures—an increase of the 2DEG current induced by light leads to an inverse effect, which represents essential changes in the FMR spectrum. [ABSTRACT FROM AUTHOR]

Magnetic properties of an ultrathin Co layer deposited on the Mo(1 1 0) or Au(1 1 1) buffers crucially depend on magnetic layer thickness and a cap layer type (Au or Mo, studied in this work). Depending on the sandwich configuration, magnetization is oriented in a perpendicular direction to the plane in the range of smaller Co layer thickness (below 2 nm) or in the sample plane for a thicker layer (3 nm). Moreover, a well-developed two-fold in-plane magnetic anisotropy occurs in the Co layer deposited on the Mo buffer. These features are correlated with crystalline structure studied with the use of numerous complementary methods: reflection high-energy electron diffraction, x-ray diffraction, x-ray reflectivity, nuclear magnetic resonance, and element-sensitive synchrotron techniques, i.e. x-ray linear dichroism and x-ray absorption near edge spectroscopy. Magnetic behaviour, exhibiting volume and surface contributions, is thoroughly discussed in terms of the buffer and cap layer type, thickness-dependent crystalline structure of the Co layer, and the interface quality. [ABSTRACT FROM AUTHOR]

Three types of antidot lattices (ADLs) based on a permalloy thin film, with increasing complexity of the unit cell: simple square, bi-component square, and wave-like ADLs were studied experimentally using both ferromagnetic resonance and Brillouin light scattering spectroscopy techniques. An additional small antidot placed in the center of the square unit cell induces significant modification of the ADL spin-wave spectrum and changes its dependence on the orientation of the in-plane applied magnetic field. The introduction of air-gaps connecting small and large antidots transforms the system into the wave-like ADL and results in further changes in the spin-wave spectrum, including a strong discrimination between two mutually orthogonal principal directions of the ADL in terms of spin-wave propagation. We also point out the impact of defected holes on the obtained spectra. The micromagnetic simulations and the calculation based on the plane wave method satisfactorily confirmed the experimental results. [ABSTRACT FROM AUTHOR]

An irreversible rotation of magnetization from in-plane to an out-of-plane direction was induced in Pt/Co/Pt epitaxial trilayers by single and multiple pulses of extreme ultraviolet (EUV) irradiations. The radial dependence of remanence, coercivity and saturation fields across the irradiated spots was studied with the help of magneto-optical techniques for the samples with various Co and Pt buffer layer thicknesses. The sample surface and magnetic ordering were investigated using atomic force and magnetic force microscopies. Based on magnetic and morphological changes, the residual stress after thermoplastic deformation in the spot area is discussed as a reason for the observed transformation. [ABSTRACT FROM AUTHOR]

The effects of shape and geometry of antidot (square, bi-component, and wave-like) lattices (ADLs) on the magnetization reversal processes and magnetic anisotropy has been systematically investigated by magneto-optical Kerr effect based microscopy. Our experimental results were reproduced by micromagnetic simulations, which highlight the qualitative agreement with the experimental results. We have demonstrated that a small antidot in the center of a unit cell in the square ADL is sufficient to induce additional easy axes with large coercive fields. In wave-like patterns, narrow channels connecting smaller and larger antidots (bi-component ADL) further drastically change the anisotropy map, creating the high coercive fields along a wide angular range (90°) of directions parallel to the channels. In simulated results, we have observed formation of periodic domain structures in all ADLs, however, in the case of a wave-like pattern it is most regular and moreover two different periodic patterns are stabilized at different applied magnetic field values. The formation of 360° domain walls were also observed in wave-like ADL where these domains are formed along the lines connecting adjacent larger and smaller antidots, perpendicular to the channels. These findings point out the possibility of exploiting ADLs with complex unit cells in magnonic or spintronic applications. [ABSTRACT FROM AUTHOR]

We describe the synthesis of submicron Y3Fe5O12 (YIG) films sputtered on GaN-based substrates and present the results of the investigation of ferromagnetic resonance (FMR) and spin wave propagation in YIG / GaN structures. It is found that spin waves propagated in deposited YIG films have low damping. At the frequency of 3.2 GHz the spin-wave damping parameter is less than . Sputtered YIG films have magnetic inhomogeneity, which gives the main contribution to the FMR linewidth. The FMR linewidth increase caused by the relaxation process is insignificant and is equal to low values (2.2–3.7% of the linewidth). The low relaxation of spin waves in deposited YIG films gives the opportunity to construct tuneable spin-wave band-pass filters with a high-quality factor on GaN substrates and to design radiation-tolerant monolithic microwave integrated circuits. [ABSTRACT FROM AUTHOR]

In this paper we calculate the pinning field associated with domain wall motion in ultrathin magnetic films, which is controlled by a high density, n, of weak defects. The pinning field is shown to vary as n5/6d[?]1/2, d being the thickness of the magnetic layer. This model is applied to a Au/Co/Au ultrathin film structure with perpendicular anisotropy, close to the spin reorientation transition. [ABSTRACT FROM AUTHOR]