Theoretical Aspects of Perpendicular Magnetic Recording Media

Andrä, W.; Danan, H.; Mattheis, R.

doi:10.1002/pssa.2211250102

Cited by 26 publications

(13 citation statements)

References 97 publications

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“…However, the reduction of dot size is limited by the superparamagnetic phenomenon. In order to further reduce the size, as well as for the application of perpendicular recording in the future, 5,6 materials with a large magnetic anisotropy and high perpendicular coercivity are needed. This can be achieved by depositing epitaxial or textured hard magnetic films with the magnetic easy axis perpendicular to the substrate.…”

Section: Introductionmentioning

confidence: 99%

High perpendicular coercive field of (100)-oriented CoFe2O4 thin films on Si (100) with MgO buffer layer

Ning

Ong

et al. 2008

Journal of Applied Physics

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CoFe 2 O 4 thin films with large perpendicular magnetic anisotropy were obtained by pulsed laser deposition on Si(100) substrates with MgO buffer layers. Transmission electron microscopy study reveals the columnar structure of these CoFe2O4 films and confirms their (100) texture. Magnetic properties of these films have been investigated in the function of substrate temperature and film thickness. A perpendicular coercivity as high as 7.8 kOe has been achieved in the CoFe2O4 film deposited at 700 °C, with a thickness of 50 nm and a grain size of 30 nm. The high coercivity mechanism is possibly associated with the magnetocrystalline anisotropy, the strain anisotropy, the shape anisotropy due to the columnar structure, and also the appropriate grain size approaching the single-domain critical value.

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Section: Introductionmentioning

confidence: 99%

High perpendicular coercive field of (100)-oriented CoFe2O4 thin films on Si (100) with MgO buffer layer

Ning

Ong

et al. 2008

Journal of Applied Physics

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“…In such films, grain boundaries provide pinning sites, which impede domain wall motion and thus enable magnetic information storage. Since areal bit densities in today's longitudinal media with in-plane magnetization rapidly approach the superparamagnetic limit [3], thin films with perpendicular anisotropy are currently investigated intensively, because a significantly higher maximum packing density has been predicted for them [4].…”

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confidence: 99%

Visualization of the Barkhausen Effect by Magnetic Force Microscopy

Schwarz¹,

Liebmann²,

Kaiser³

et al. 2004

Phys. Rev. Lett.

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By visualization of the Barkhausen effect using magnetic force microscopy we are able to provide detailed information about the physical principles that govern the magnetization reversal of a granular ferromagnetic thin film with perpendicular anisotropy. Individual Barkhausen volumes are localized and distinguished as either newly nucleated or grown by domain wall propagation. The Gaussian size distribution of nucleated Barkhausen volumes indicates an uncorrelated random process, while grown Barkhausen volumes exhibit an inverse power law distribution, which points towards a critical behavior during domain wall motion.

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“…In thick samples ma onetisation reversal remains localised in the vicinity of the ""original nucleation sites. Reversed domains stabilise remaining areas with positive magnetisation [26], leading to small steps in the demagnetisation curve. fig.…”

Section: Hysjeresis Propertiesmentioning

confidence: 99%

“…The relative strength of exchange coupling versus strayfield coupling decreases with increasing grain size. Stray field coupling has the tendency to broaden the transition between domains [26]. For the calculation of the wall profiles the magnetisation component parallel to the film nonnal has been averaged over 36 radial directions.…”

Section: Hysjeresis Propertiesmentioning

confidence: 99%

Micromagnetic Simulation of Mo-Multilayers

Schrefl

Fidler

1996

J. Magn. Soc. Jpn.

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~ Micromagnetic finite element calculations rigorously describe the effects of microstructural features on the magnetic properties of ColPt multilayer thin films. Within the framework of static micromagnetism. the hysteresis properties result from subsequent minimum energy solutions for decreasing or increasing applied fields. The concurrent modelling of inhomogeneous magnetic states within the individual grains and of co-operative reversal processes leads to a large-scale optimisation problem. In order to reduce the number of variables. shell elements which account for the multilayer structure and a magnetic vector potential to treat the long-range stray fields are used. Micromagnetic calculations of demagnetisation curves and domain structures in ColPt multilayer systems show a qualitative agreement with experimental data obtained from Lorentz electron microscopy. The nucleation field of ColPt multilayer increases with improving texture. Spatial fluctuations of the anisotropy directions from grain to grain create barriers for domain wall . motion. The pinning field increases with increasing grain size. The coercive squareness improves with decreasing number ofbilayers. The ac-demagneJised state shows a maze-like structure. The underlying skeleton shape of the domain structure remains substantially unchanged under an applied field. The transition width and the domain wall jaggedness increase with decreasing quality of texture and increasing grain size.

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Theoretical Aspects of Perpendicular Magnetic Recording Media

Cited by 26 publications

References 97 publications

High perpendicular coercive field of (100)-oriented CoFe2O4 thin films on Si (100) with MgO buffer layer

High perpendicular coercive field of (100)-oriented CoFe2O4 thin films on Si (100) with MgO buffer layer

Visualization of the Barkhausen Effect by Magnetic Force Microscopy

Micromagnetic Simulation of Mo-Multilayers

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