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
    Effects of grain size dispersion on noise in longitudinal thin film media : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 5548-5550 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of grain size dispersion on medium noise in longitudinal thin film recording media is studied by micromagnetic modeling. A previous micromagnetic model has been extended for modeling films with grain size variation. It is found that for the typical thin film media, moderate grain size dispersion in the film does not affect the media noise at low recording densities. At high recording densities, when adjacent transition boundaries percolate, the film with grain size dispersion exhibits a less degree of superlinear noise enhancement than the film with identical size grains. It is concluded that for films with medium noise dominated by magnetic interactions, moderate grain size dispersion slightly suppresses the collective magnetization processes at high recording densities, thereby, reducing medium noise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Method for investigating the reversal properties of isolated barium ferrite fine particles utilizing magnetic force microscopy (MFM) : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6716-6718 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The reversal properties of isolated barium ferrite recording particles with Co-Ti substitution (BaFe12−2xCoxTixO19) are studied by a newly developed magnetic force microscopy (MFM)-based technique. The size dependence of the switching field on particles with diameters ranging from 30 to 80 nm were investigated. A decrease in the switching field was observed, which corresponds to a decrease in the particle diameter below 50 nm. This indicates thermally assisted switching in small size particles. As the diameter increases, the switching field reaches a maximum at 55 nm then sharply decreases. An atomic force microscopy (AFM) profile of the particle's thickness shows that the aspect ratio variation among these particles cannot account for the observed difference in the switching field. Thus, it is concluded that incoherent reversal is occurring in particles with diameter greater than 60 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Micromagnetic study of dynamic domain instability in magnetoresistive sensors (abstract) : 37th Annual conference on magnetism and magnetic materials (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6241-6241 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Dynamic domain instability in magnetoresistive sensors produces noise in the output voltage pulses and forces complex head designs to suppress the irregular domain activities. In this paper, the micromagnetic modeling study of dynamic domain instability is presented. A Permalloy magnetoresistive sensor 10 μm in width, 2.5 μm in height, and 200 A(ring) in thickness is modeled by a two dimensional array containing 512×128 cubic elements with identical intrinsic magnetic properties of Permalloy material. The Landau–Lifshitz equation is utilized for calculating the dynamic magnetic domain configurations as well as structures within domain walls. The study focuses on the transient processes that generate complex multidomain structures and the irregular dynamic domain activities. Figure 1 shows a simulated static "single'' domain configuration, obtained by initially aligning the magnetization along the long axis of the Permalloy stripe. Circular edge domains are formed with patterns well agree with experimental observations. A high frequency (200 MHz) sinusoidal external field (amplitude 40 Oe) is then applied vertically with 10° deviation. Figure 2 shows the transient domain configuration at the time t=0.6T (T=period). The center portion of the stripe have become multidomain with irregular domain configuration and 180° Neel walls containing irregularly distributed Bloch lines and crossties. Note the irregularity of the domain configuration even though the material is homogeneous. The magnetization within the Neel walls alternates its direction along the walls. Detailed analysis of the onset of the multidomain state will be presented. Investigation of dynamic domain behavior under various bias schemes will be reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352710
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Self-organized behavior in thin-film recording media : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4709-4711 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetization domain structures in thin metallic films utilized as recording media are modeled by a cellular automation on a two-dimensional triangular lattice. This alternative approach permits significantly large arrays ((approximately-greater-than) 106 grains) to be investigated as compared to an exact calculation (≈ 5 × 103 grains). Thus a study of the statistical distribution of the domain sizes and their power spectra can be made. Magnetostatic interactions and intergranular exchange coupling are included in a simple manner so that collective behavior is incorporated. It is found that away from the saturation remanent state, the distribution of the size of the avalanches (or the number of sites reversed in a single reversal sequence) follows a power-law behavior: D(S) = AS−α where S is the avalanche size and α varies in the vicinity of 1 depending on the interaction strength. The reversal field keeps the system marginally stable. It is found that the reproduce noise power varies as the derivative of the M-H loop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348255
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Reversal mechanisms and domain structures in thin-film recording media (invited) : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 6084-6089 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetization reversal in longitudinal and perpendicular thin films is studied via computer simulation. Collective micromagnetic processes and the formation of magnetization patterns driven by magnetostatic interactions and intergranular exchange coupling is analyzed. In longitudinal thin films, it is found that a reversal starts by formation of magnetization vortices. The collective formation of vortices yields elongated reverse regions along the direction of the applied field. Intergranular exchange coupling enhances these magnetization structures and results in large-size domains. Reversal of a typical perpendicular film (CoCr) consists of discrete nucleation processes. Each individual process is characterized by a planar chain nucleation mode. These collective micromagnetic processes cause film magnetic properties to be significantly different from those of a simple assembly of noninteracting grains. Medium noise in perpendicular films occurs mainly away from transitions in distinct contrast to longitudinal films in which the noise is concentrated at transition centers. Intergranular exchange coupling increases the medium noise in all films.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347776
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Angular dependence measurement of individual barium ferrite recording particles near the single domain size : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5553-5555 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The switching field angular dependence measurement of individual barium ferrite recording particles with sizes ranging from 55 to 75 nm in diameter were measured via magnetic force microscopy technique. These experimental measurements were then used as a basis to investigate their nucleation mechanism and intrinsic switching modes. Our findings indicate that the effects nonuniform doping of Co-Ti can significantly affect the easy axis nucleation field and the switching mode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355686
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Micromagnetic study of narrow track orthogonal giant magnetoresistive heads : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6388-6390 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Orthogonal narrow track magnetoresistive heads using giant magnetoresistive multilayers have been studied by micromagnetic modeling. The modeling shows that the hysteresis arises from irreversible switching of the edge-curling wall (ECW) on the side edges of the giant magnetoresistive (GMR) sensor layers. Effects of thickness and interlayer exchange coupling on the switching of the ECW are analyzed. It is also found that if the interlayer exchange coupling is ferromagnetic, the GMR orthogonal head has significant high signal amplitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355359
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Damping capacity of layered materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 7784-7789 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Extensive measurements of the internal friction in a variety of layered materials such as graphite, metal dichalcogenides (MoS2, TiS2, NbSe2, TaS2, TaSe2, and TaTe2), and montmorillonite clays are reported. The internal friction of these layered materials exhibits features similar to those observed in graphite. In particular, a high temperature internal friction plateau develops at a temperature that is characteristic of the material. The physical mechanism for this plateau is discussed. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357956
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Bicrystal advanced thin-film media for high density recording : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6129-6131 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new type of thin-film recording media with advanced microstructure: the bicrystal film, has been studied experimentally. The easy axes of the bicrystal films are oriented along two specified orthogonal directions in the film plane. In this study, an LiF single crystal substrate with (100) orientation is utilized to obtain the Cr monocrystal underlayer with (100) orientation, and on top of the (100)Cr underlayer the CoCrTa with (112¯0) texture was grown epitaxially. X-ray and transmission electron microscopy (TEM) diffraction studies confirm the fabricated thin-film media has the bicrystal microstructure. The magnetic properties of the bicrystal films have demonstrated very high coercivity (HC∼3000 Oe) and coercive and remanent squareness (S*∼0.9, S∼0.9), all desired for high areal density magnetic recording. The in-plane hysteresis loops of the fabricated films show fourfold symmetry which is the characteristic of the bicrystal microstructure. The effects of Cr underlayer thickness on the magnetic properties of the bicrystal film has also been studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355431
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Modeling of thin-film media with advanced microstructure for ultrahigh density recording : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6135-6137 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetic thin films with subgrain structure, or nanocrytalline films are studied via micromagnetic modeling. The subgrain nanocrystallites form a bicrystal structure inside a normal grain, due to proper epitaxial growth. It is shown that a relatively small but nonzero exchange coupling through normal grain boundaries is critical for obtaining high coercive squareness. Maintaining low exchange coupling between subgrains in a normal grain is important for achieving low transition noise. The calculation shows that films with this microstructure can have S*≈0.95 and a signal-to-noise ratio of 36 dB at 385 KFCI with 1-μm track width. Such film microstructure is practically achievable in principle and is suited for future high recording density applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355433
    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...