Showing papers by "Andrzej Maziewski published in 2006"
TL;DR: In this article, a general view of geometrically constrained magnetization distributions is given, showing that by shrinking the lateral size of a sample one can induce reorientation from an in-plane to an out-of-plane magnetization state.
Abstract: Magnetization states of laterally limited ultrathin nanostructures (semi-infinite film edges, wires, and disks) with low magnetic uniaxial anisotropy are studied analytically and by micromagnetic simulations. A general view of geometrically constrained magnetization distributions is given. By shrinking the lateral size of a sample one can induce reorientation from an in-plane to an out-of-plane magnetization state. As examples, magnetic phase diagrams have been calculated for cobalt nanowires and disks. In low-anisotropy nanodisks magnetization distributions like an out-of-plane domain-patterned vortex and a domain-patterned leaf are found.
20 citations
TL;DR: An ellipsometric configuration for measurement of complex transverse magneto-optical Kerr effect that uses photoelastic modulator (PEM) is described in this paper, where the real and imaginary parts of the complex transversal Kerr effect are represented as small perturbations of ellipsomet angles $\psi$ and $\Delta$.
Abstract: An ellipsometric configuration for measurement of complex transverse magneto-optical Kerr effect is described that uses photoelastic modulator (PEM). The real and imaginary parts of the complex transverse Kerr effect are represented as small perturbations of ellipsometric angles $\psi$ and $\Delta$. The measurement based on null ellipsometry and zone averaging gives high signal typical for modulation techniques and insensitivity to other magnetisation components and system imperfections. The method is demonstrated by the measurement of transverse component during magnetisation reversal in thin cobalt film.
18 citations
TL;DR: In this article, the authors report on micromagnetic simulations of magnetization distributions in infinite and laterally limited ultrathin magnets of different geometries, revealing the crucial role of the finite-size effect on magnetization states in nanowires and disks.
Abstract: We report on micromagnetic simulations of magnetization distributions in infinite and laterally limited ultrathin magnets of different geometries. We reveal the crucial role of the finite-size effect on magnetization states in nanowires and disks. In low-perpendicular-anisotropy nanomagnets, out-of-plane magnetization states can be achieved by varying geometry and/or lateral size of the sample.
8 citations
TL;DR: In this article, the evolution of magnetization distributions in samples with low magnetic perpendicular-anisotropy described by the quality factor Q (the relation between anisotropic and demagnetization energies) is reviewed.
Abstract: We review the evolution of magnetization distributions in samples with low magnetic perpendicular-anisotropy described by the quality factor Q (the relation between anisotropy and demagnetization energies). Infinite ultrathin films, nanowires and disks are studied using real magnetic parameters determined for ultrathin cobalt. By micromagnetic simulations we demonstrate novel types of magnetization distributions. Reconstructions of magnetization distributions at the spin reorientation transition (RPT) from the perpendicular to in-plane state are discussed. We show that the sample edge significantly affects the magnetization distribution performance and shifts the RPT to lower Q (higher nanostructure thickness) and/or to higher amplitude of in-plane applied magnetic fields in comparison to those in laterally infinite films. A unified thermodynamic treatment is presented for reorientation transitions in nanowires. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
8 citations
TL;DR: In this article, the thickness and field-driven evolutions of magnetization distributions in ultrathin cobalt films are studied by micromagnetic simulations, and the edge effect was shown to extend the existence of out-of-plane magnetizations states behind the reorientation phase transition thickness.
3 citations
TL;DR: In this article, the magnetic anisotropy changes in epitaxial ultrathin Co films grown on vicinal sapphire substrates with different miscut angles were investigated.
Abstract: The aim of the work is to study the magnetic anisotropy changes in epitaxial ultrathin Co films grown on vicinal sapphire substrates with different miscut angles. Changes of the in-plane magnetic anisotropy symmetry were deduced from magnetooptical hysteresis loops shape and angular dependence analysis of the resonance field measured in the sample plane. Two-fold and four-fold symmetry of the in-plane anisotropy was observed for different miscut angles. The experimental data are discussed taking into account the following energy contributions: (i) demagnetization; (ii) perpendicular uniaxial anisotropy (iii) and step-induced uniaxial anisotropy. Magnetic anisotropy constants are fitted to the experimental results for different miscut angles.
2 citations
TL;DR: In this article, the thermal-driven evolution of stripe domain structures in ultrathin magnetic films is analyzed with regard to temperature dependencies of the film magnetic parameters in the vicinity of the Curie temperature or points of the spin reorientation.
Abstract: The thermal-driven evolution of stripe domain structures in ultrathin magnetic films is analyzed with regard to temperature dependencies of the film magnetic parameters In the vicinity of the Curie temperature or points of the spin reorientation the equilibrium stripe domain period was found to exponentially decrease with increasing temperature It is shown that the temperature dependence of the characteristic length is the key parameter controlling the domain period changes Irreversible and reversible changes of the domain period as well as the so-called inverse domain melting are discussed
2 citations
TL;DR: The idea of a global Web library is fast becoming a reality and the Internet continues to revolutionize many aspects of daily life and has become the authors' most powerful tool for transmitting knowledge.
Abstract: Created by physicists, the Internet continues to revolutionize many aspects of daily life and has become our most powerful tool for transmitting knowledge. In fact, the idea of a global Web library is fast becoming a reality.
2 citations
TL;DR: In this article, the authors describe equilibrium and nonequilibrium stripe domains in ultrathin magnetic films with uniaxial perpendicular anisotropy and introduce the notion of domain chemical potential to analyze metastable domains and their thermal and field evolution.
Abstract: We describe equilibrium and nonequilibrium stripe domains in ultrathin magnetic films with uniaxial perpendicular anisotropy. The notion of the domain chemical potential is introduced to analyze metastable domains and their thermal and field evolution. For ultrathin cobalt films the domain period is calculated as a function of the coercivity field. We demonstrate that the period of metastable domains can significantly differ from the period of equilibrium domains. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
2 citations
Journal Article•
TL;DR: In this article, the authors studied the dendritic structures in gold-enveloped cobalt ultrathin films of thicknesses slightly below the thickness at which the reorientation from a perpendicular magnetization state to the in-plane state takes place.
Abstract: We report on the study of dendritic domain structures in gold-enveloped cobalt ultrathin films of thicknesses slightly below the thickness at which the reorientation from a perpendicular magnetization state to the in-plane state takes place. In these films, magnetization reversal proceeds through the dendritic growth of domains. A magnetic after-effect was observed. We reveal the mechanism and key parameters controlling the dendritic growth of magnetic domains.
1 citations
TL;DR: In this article, the correlation between structural and magnetic properties of Au(111)/Co(0001)/Au(111) sandwiches with perpendicular magnetic anisotropy, grown by molecular beam epitaxy, has been studied in details.
Abstract: The correlation between structural and magnetic properties of Au(111)/Co(0001)/Au(111) sandwiches with perpendicular magnetic anisotropy, grown by molecular beam epitaxy, has been studied in details. Thermal treatment in the range between room temperature and 300 °C at various stages of samples growth process as well as after its completion is applied as a factor modifying the structure of studied specimens. Annealing at 150 °C does not affect substantially either crystalline structure or perpendicular magnetic anisotropy. At 250 °C the RHEED pattern of Co layers reveals the loss of the lattice coherence with Au underlayer and the analysis of synchrotron radiation reflectometry leads to the conclusion that the continuity of Co layers is lost. Structural evolution upon thermal treatment is well correlated with changes of magnetic anisotropy studied by magnetooptical Kerr effect. After annealing at 250 °C magnetization switches from out-of-plane to in-plane orientation, which is explained in terms of interfacial and magnetoelastic contributions to the sample magnetic anisotropy. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Journal Article•
TL;DR: In this article, the evolution of the domain structure during magnetization reversal was studied for various orientations of the magnetic field relative to the anisotropy easy axis using a longitudinal Kerr MO microscope.
Abstract: Magnetization reversal and domain structures in thin Co films in the thickness range 2 < d < 100 nm with in-plane magnetic anisotropy were studied. Both magneto-optical (MO) vector magnetometry and MO microscopy were used. A crossover of in-plane anisotropy symmetry from two-fold to six-fold was observed with increasing thickness of the Co layer from 2 nm to 100 nm. The evolution of the domain structure during magnetization reversal was studied for various orientations of the magnetic field relative to the anisotropy easy axis using a longitudinal Kerr MO microscope.
TL;DR: In this paper, the authors describe the processes for reversal of the magnetization of ultrathin Co magnetic films on Si(1/1/ 1) vicinal substrates, taking into account the following contributions to the total magnetic anisotropy energy.
Abstract: Micromagnetic simulations were performed to describe the processes for reversal of the magnetization of ultrathin Co magnetic films on Si(1 1 1) vicinal substrates. The micromagnetic model is discussed, taking into account the following contributions to the total magnetic anisotropy energy: perpendicular uniaxial anisotropy, step-induced uniaxial in-plane anisotropy and magnetocrystalline anisotropy. There is good agreement between the results of the simulation and the experiment.