ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Computer simulation of magnetization states in a magnetic thin film consisting of magnetostatically coupled grains with randomly oriented cubic anisotropy : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6513-6515 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Computer simulations are performed to model the magnetically soft but isotropic behavior of an Fe-Si-Al alloy film. Solving the Landau–Lifshitz–Gilbert equation under the periodic boundary condition, magnetization states are simulated in a single layer film represented by a two-dimensional array of closely packed hexagonal prisms. Each prism represents a single crystal grain which is assumed to have randomly oriented cubic anisotropy and similar magnetic parameters as those of an Fe-Si-Al alloy film. It is also assumed that the magnetization is always uniform inside each grain and the exchange coupling among grains is zero. It is observed that the film without an external field shows a demagnetized state with considerably dispersed domain configuration where the characteristic wall and vortex structures are formed. It is also observed that the film is switched by applying an external field of which intensity depends on the cubic anisotropy constant of the grains. Analyzing the sum of exerting torque to the magnetization of grains, it is derived that the torque by cubic anisotropy is completely balanced with that by demagnetizing field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352598
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Computer simulation of thin-film media noise using an autocorrelation function along the track direction (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1190-1200 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The causes of thin-film media noise are discussed by deriving a formula which shows a direct relationship between the noise spectrum and the magnetization configuration of a thin-film medium. This formula is derived by Fourier-transforming the autocorrelation function of jMx-Mz along the track direction, where Mx and Mz are the longitudinal and vertical components of magnetization, respectively. Noise and signal spectra are computed by means of this formula. The computed noise spectra are the maximum for a relatively long wavelength. Their form and intensity are shown to be strongly affected by the anisotropy constant and the axis orientation of easy magnetization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356475
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Method of measuring anisotropy field of a recording medium investigated by computer simulation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5303-5308 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Three methods of measuring anisotropy field of a recording medium with the easy directions in the film plane were examined by computer simulation: (1) applying magnetic fields in a direction slightly tilted from the hard direction of the medium, (2) using rotational hysteresis loss, (3) applying perpendicular field to the film plane. The anisotropy fields obtained with these methods were smaller than the intrinsic anisotropy fields of grains (or particles). A method is proposed for obtaining the intrinsic anisotropy field of grains. In this method, magnetic torques are measured out-of-plane of a film. A method, which is an extension of the above method (1), for measuring the distribution of easy direction, is also examined and a revised method is proposed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359285
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of longitudinal bias field on magnetization distribution in magnetoresistive head with shield films (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1036-1040 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetization distribution in the magnetoresistive (MR) film has been calculated by self-consistently solving the three-dimensional field of the MR head. The magnetization distribution was calculated based on the Landau–Lifshitz–Gilbert equation and the head field was obtained by the Maxwell equation. The longitudinal bias field for the domain control was generated by exchange-coupled antiferromagnetic or permanent magnetic films which were formed outside the sensing region of the MR film. The resistance change of the MR film was calculated from the magnetization distribution with shield films and without shield films. It was found that the resistance change with the antiferromagnetic film without the shields was about two times larger than that with the permanent magnetic film with the remanence Br of 0.7 T. The difference between them was reduced when the shields were formed because the stray field from the permanent magnetic film which is applied to the MR film was decreased by the shields. Further, the effect of the longitudinal bias field on the magnetization distribution was analyzed for the MR film without the shields. The influence of the antiferromagnetic film reached the region of 2–3 μm from the end of the film, while that of the permanent magnetic film reached more than 10 μm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356484
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Simulation of magnetization distribution in magnetoresistive film under a longitudinal bias field (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5666-5671 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of longitudinal bias field, used for domain control on the magnetization distribution in a magnetoresistive (MR) film, have been investigated by computer simulation. The longitudinal bias field was generated by an exchange-coupled antiferromagnetic or permanent magnetic film formed on the MR film outside the sensing region. It was assumed that the magnetization in the part of the MR film on which the bias-generating films were formed was fixed along the easy axis. The spatial sensitivity of the MR film along the track width was evaluated by calculating the dependence of the resistance change on the position of a narrow track recording medium. It was found that the resistance change in the MR film with the anti-ferromagnetic film was roughly twice as large as the change in the film with the permanent magnetic film. The asymmetric sensitivity profile with respect to reflection about the track width mid-plane was also obtained. The asymmetry in the track sensitivity profile was found to be caused by three factors: asymmetric magnetization distribution about the track width mid-plane due to the transverse bias field, the difference in angular changes in the magnetization direction in the left and right regions facing the recording medium, and anisotropic flux propagation in the MR film.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354181
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    S/N ratio of thin-film media estimated by computer simulation (abstract) : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 5578-5578 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This paper derives a formula that shows a direct relationship between the noise spectrum and the magnetization configuration of a thin-film medium. This formula was obtained by Fourier transforming the down-track autocorrelation function of jMx-Mz, where Mx and Mz are the longitudinal and vertical components of magnetization. The formula takes into account not only the variance of the magnetization deviation, which is generally used to estimate media noise, but also the correlation between deviations in magnetization. This lets us calculate the noise power spectrum as well as the signal power, once the magnetization configuration in a medium is obtained, which means that the magnetic microstructures such as vortex, zig-zag domain, etc., are automatically included in noise calculation. To investigate the relationships between the noise properties and the magnetic properties of media with various anisotropy fields (Hk), axis orientation of easy magnetization, and stiffness constants (A), recorded magnetization configurations were simulated using the Landau–Lifshitz–Gilbert equation.1,2 The easy axis was oriented from uniaxial direction to random direction in plane. The simulated noise power spectra were maximized at a relatively long wavelength, which was varied by changing Hk, or the easy axis orientation. The noise power was strongly influenced by Hk and the axis orientation of magnetization. This confirms that preferential orientation along the longitudinal direction and a large Hk are effective for improving the S/N ratio. On the other hand, the stiffness constant less improved media noise than Hk and axis orientation, suggesting that the preferential orientation of the easy axis is more effective to reduce media noise than isolating magnetic grains.1
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Computer simulation of magnetization reversal in fine hexagonal platelet particles with defects : 35TH ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS San Diego, California (USA) 29 Oct−1 Nov 1990 (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4847-4849 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Landau–Lifshitz–Gilbert equation is used to investigate the switching fields and mechanisms of fine hexagonal platelet particles which have three types of defects in comparison with a nondefect particle. Two of the defects are surface defects, one with an area more than 50% of the hexagon and the other much less than 50%. The third defect is not a surface defect but a defect which extends from the top to bottom surface. The differences between the switching fields of these particles are small, at most 12%. The angular dependence of the switching fields of these particles is similar to the ones derived from the coherent rotation mode. The switching mechanisms of the particles change with applied field. The nondefect particle switch in a normal vortex mode and the particles with defects switch in a mixture of normal vortex and coherent rotation-like mode at the applied field=Hsw (switching field). Most of them switch in a twisted vortex mode at the applied field=3 × Hsw. But in surface defect particles, whose defect area is more than 50% of the hexagon, the switching mechanism hardly changes from a coherent rotation-like mode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348251
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Computer simulation of magnetization reversal: The effect of shape and uniaxial crystalline anisotropy : 35th annual conference on magnetism and magnetic materials San Diego, California (USA) 29 Oct − 1 Nov 1990 (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4850-4852 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Landau–Lifshitz–Gilbert equation has been used to compare the hysteresis loops and magnetization-reversal mechanisms of a cubic particle, with uniaxial crystalline anisotropy, and a 2:1-aspect-ratio elongated particle. The switching fields of these particles were 700 Oe. The cubic particle exhibited a square hysteresis loop, but the elongated particle had a nonsquare hysteresis loop due to the tilting of spins in the surface layers. Magnetization reversal for the elongated particle was initiated at the surface layers. For the cubic particle the reversal was initiated at an edge of the particle and spread through to the central elements. Differences between the hysteresis loops and reversal mechanisms, for the different particles, are attributed to the different nature of the magnetic anisotropies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Dynamical calculation of magnetization reversal in elongated particles (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5146-5148 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Landau–Lifshitz–Gilbert (LLG) equation is directly solved to investigate squareness and time-dependent magnetization changes of elongated particles. Squareness scarcely changes until the particle size exceeds some critical value. The critical value increases with increasing aspect ratio. It was found that there are three kinds of magnetization reversal mechanism in elongated particles: flower1, flower2, and vortex particles. Some time interval is necessary for the irreversible transition to occur in all cases. In a flower1 particle, the transition occurs from the top and bottom planes. In flower2 and vortex particles, the irreversible transitions occur from vortex states. In a flower2 particle, during the irreversible transition process, all magnetic moments at the top and bottom planes rotate to the same direction; consequently, some magnetic moments rotate to the antiapplied-field direction and then rotate to the applied-field direction. In a vortex particle, each magnetic moment at the top and bottom planes rotates to the applied-field direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344644
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Computer simulation of magnetization reversal in fine hexaferrite particles (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5143-5145 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetization reversal mechanisms in hexaferrite particles were investigated by computer simulation. The Landau–Lifshitz–Gilbert equation discretized according to the Crank–Nicolson method was solved numerically. The computing region was divided into triangular prisms of equal size which are accommodated to the contour surfaces of the hexagonal particle. The demagnetizing field was calculated using a finite-grid method based on the triangular prisms. The mode of reversal was found to be extremely dependent on the thickness of the particle. In the case of a thin particle, the reversal started at the particle center and then spread to the edges of the particle almost coherently at the same radius. In a thick particle, vortexes of magnetization with opposite polarities of rotation were generated at the top and bottom surfaces, and the switching was incoherent over the particle thickness. In the case of an intermediate thickness, the reversal began at the particle center, but it spread to the particle edges incoherently. The formulation of the calculation and the results of simulation are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344643
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...