Dependence Of Magnetization Reversal Research Articles

The Spin Wave Gap and Switching Field in Thin Films with In-Plane Anisotropy

In this paper, we have calculated the spin wave gap and the angular dependence of magnetization reversal in a single-layer thin magnetic film that includes the strong perpendicular magnetic anisotropy and in-plane anisotropy. The film is assumed to be under the influence of the out-of-plane direction of the applied magnetic field at zero temperature. Using the quantum model, it is shown that the calculated equations present a nonzero spin wave gap at zero magnetic field which is strongly affected by anisotropies. The effects of the in-plane anisotropy and the role of the applied field were examined. We also discussed a simple theoretical model for the angular variation of switching field by using a quasi-classical argument. We used some constants in connection with experimental data which are reported for chromium telluride thin films grown by molecular beam epitaxy.

Magnetization reversal dependence on effective magnetic anisotropy in electroplated Co–Cu nanowire arrays

Arrays of Co(100−x)Cu(x) (0 ≤ x ≤ 27) nanowires with 45 nm of diameter and 18 μm in length, have been potentiostatically electrodeposited into the hexagonally self-assembled nanopores of anodic alumina membranes.

Frequency dependence of magnetization reversal in thin Fe(100) films

We have studied the magnetization reversal of epitaxial Fe(100) films in an ac magnetic field as a function of frequency between 0.1 and 1.2 MHz by polarized neutron reflectivity. Different modes of magnetization reversal are excited depending on the ac field frequency, those with domain nucleation and propagation, and those with a coherent magnetization rotation. At low frequencies the magnetization follows the external field adiabatically via nucleation and propagation of antiparallel 180${}^{\ensuremath{\circ}}$ domains. At higher frequencies additional 90${}^{\ensuremath{\circ}}$ domain walls are being nucleated and propagate. Beyond 0.5 MHz, the magnetization reversal becomes progressively suppressed and finally comes to a stop at about 1 MHz.

Exchange Spring Effect in RF-Annealed Amorphous Co55Fe25B10Si10 Ribbons

Exchange spring systems are promising for application in high performance data storage, novel permanent magnets and some other technologies. In this work, we report the exchange spring behavior in RF-annealed amorphous Co55Fe25B10Si10 ribbons. The measurements on magnetic and structural properties of irradiated samples revealed that the RF radiation has affected just the outermost surface layers of the ribbons. We have also reported the angular dependence of magnetization reversal and coercivity of a typical annealed sample. Our study shows that the RF annealing can be supposed to be a simple and easy manner to produce bilayer exchange spring systems.

Angular dependence of magnetization reversal in exchange-biased Co∕Pt multilayer with perpendicular magnetic anisotropy

The magnetization reversal in exchange-biased (Co∕Pt)5∕Co∕FeMn multilayer with perpendicular magnetic anisotropy has been studied depending on the angle between an applied field and the easy axis (the normal of the film plane). The results show different characters from that in most in-plane exchange bias systems. In a large angular range, the magnetization rotates first toward the adjacent direction of easy axis for both descending and ascending branches because perpendicular magnetic anisotropy is much larger than unidirectional exchange anisotropy. With increasing the angle from 0° to 90°, the magnitude of the exchange bias field decreases, but the coercivity increases due to domain nucleation and propagation included in the magnetization reversal process. The angular dependence of magnetization reversal shows no hysteresis between clockwise and counterclockwise rotations.

Temperature dependence of magnetization reversal in magnetostrictive glass-coated amorphous microwires

Temperature dependence of magnetization reversal in magnetostrictive glass-coated amorphous microwires

Angular dependence of magnetization reversal process in patterned Co thin films

We measured longitudinal and transverse magnetooptic Kerr effect loops to understand the angular dependence of magnetization reversal in an array of 5 /spl mu/m /spl times/ 25 /spl mu/m rectangular thin Co bars with uniaxial anisotropy. When the magnetic field is applied close to the hard axis, the reversal is dominated by coherent rotation; when the field is applied close to the easy axis, the reversal is caused by domain-wall unpinning and the coercive fields observe the relation H/sub c/ = H/sub 0//cos /spl theta//sub 0/. For the other orientations, the magnetization first rotates smoothly at larger fields and then switches irreversibly by domain-wall unpinning.

Angular dependence of magnetization reversal in γ-Fe/sub 2/O/sub 3/ single particles: An experimental and modelling study

The switching field for isolated /spl gamma/-Fe/sub 2/O/sub 3/ magnetic particles has been investigated as a function of the applied field angle both experimentally and numerically. Micromagnetic simulations for a typical measured particle with cubic crystalline directions of and with respect to its long axis were compared directly with experimental results. At large applied field angles, the agreement between experimental results and numerical simulations was poor. However, at the smaller applied field angles the simulations gave reasonable agreement with the experimental results.

Dependence of magnetization reversal on the crystallite size in MnBi thin films: Experiment, theory, and computer simulation

A micromagnetic model is proposed to explain the magnetization reversal of thermally evaporated MnBi thin films. The model assumes that the films consist of grains on a square lattice with perpendicular magnetic anisotropy. In order to describe the magnetic reversal of a particular grain, dipole coupling, wall energy, Zeeman energy, and an energy barrier for the reversal of a single grain are taken into account. Disorder is included by random fluctuations of the lateral grain size in the Zeeman-energy term. The simulation is carried out by using a Monte Carlo method. The experimentally observed decrease in coercivity with increasing film thickness is accurately described by the model and can be explained by an increase in lateral grain size. The asymmetry of the slope of the hysteresis curve of thicker MnBi films can be understood in terms of disorder. In the presence of fluctuations in grain size, large grains reverse more easily than small ones leading to an asymmetry of the slope of the hysteresis curve. \textcopyright{} 1996 The American Physical Society.