CoFe-IrMn exchange-coupled soft underlayers for perpendicular media

Jung, Hongsik; Doyle, William

doi:10.1109/tmag.2002.801813

Cited by 25 publications

(19 citation statements)

References 11 publications

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“…Typical magnetic domain sizes in thin films are in the micrometer regime, although large quasi-single-domain states have been achieved by exchange coupling soft magnetic layers to a synthetic antiferromagnet heterostructure [12,13]. Here we uncover macroscopic magnetic domains in single amorphous SmCo thin films, without the use of a pinning layer.…”

Section: Introductionmentioning

confidence: 91%

Giant magnetic domains in amorphous SmCo thin films

et al. 2014

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The potential for tuning of magnetic properties and the exceptional uniformity are among the features that make amorphous magnetic materials attractive for technology. Here it is shown that the magnetization reversal in amorphous SmCo thin films takes place through the formation of giant magnetic domains, over a centimeter across. The domain structure is found to be dictated by the direction of the imprinted in-plane easy axis and the film boundaries. This is a consequence of the size of the anisotropy and the structural uniformity of the films, which also allows the movement of millimeter-long domain walls over distances of several millimeters. The results demonstrate the possibility of tailoring the magnetic domain structure in amorphous magnets over a wide range of length scales, up to centimeters. Moreover, they highlight an important consequence of the structural perfection of amorphous films.

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Section: Introductionmentioning

confidence: 91%

Giant magnetic domains in amorphous SmCo thin films

et al. 2014

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“…A read-write speed was 10 m/sec. , and an antiferromagnetic layer to pin the FeCo film 10) . A Pt underlayer is effective in increasing the crystal orientation of the IrMn, which is necessary in order to enhance the exchange coupling energy between the FeCo and the IrMn films.…”

Section: E E Xperimen Tmentioning

confidence: 99%

Influence on the Recording Performance due to exchange coupling field of Soft Underlayer in Perpendicular Recording Media

Shintaku

2009

J. Magn. Soc. Jpn.

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CoPt-TiO2 granular-type media with extremely thin Ru intermediate layer were prepared on a highly oriented high-Bs FeCo soft underlayer (SUL) pinned by an IrMn antiferromagnetic layer. Although the increase of the IrMn antiferromagnetic layer thickness deteriorates the crystal orientation of the media, the magnetic properties of the recording layer were little changed. On the other hand, the Hch (Hc in the hard axis direction) of the SUL were greatly decreased and the Hex (exchange coupling field) of the SUL was largely increased. The Hex of about 10 Oe is effective for the magnetic domain control of the SUL. The recording performance was measured by using a SPT head. The S/N increased as the IrMn layer thickness was increased. This improvement of the recording performance seems to be responsible for the magnetic domain control by the IrMn antiferromagnetic layer. Moreover, enough effect was obtained by Hex of about 10 Oe under environment of conventional spin stand measurement system. K Key wor ds : perpendicular magnetic recording, CoPt-TiO2 granular-type media, IrMn antiferromagnetic layer, FeCo soft underlayer. 1 1. I ntro duction Perpendicular magnetic recording systems were proposed about 30 years ago as a method suitable for high-density magnetic recording 1) . At present they are adopted in almost all commercial hard disk drives.Reduction of the film thickness of an intermediate layer between a recording layer and a soft underlayer (SUL) is needed for higher recording densities. Some approaches to reduce the intermediate layer thickness were reported 2)-3) . However, obtained intermediate layer thicknesses were not very thin. So I proposed CoPt-TiO2 media with a highly oriented FeCo SUL with a high-Bs of 2.45 T and a thin Ru intermediate layer 4) . Due to a new designed medium 5)-6) , the minimum Ru intermediate layer thickness for obtaining the squareness ratio (SQ) more than 0.99 was reduced down to 1.6 nm 7) . The oscillatory interlayer magnetic interaction between the recording layer and the SUL was also observed as a function of Ru intermediate layer thickness for the media with such an extremely thin Ru intermediate layer.In the above-mentioned media, the SUL is pinned by an IrMn antiferromagnetic layer. As it is desirable that the IrMn antiferromagnetic layer is thin to increase the crystal orientation of the FeCo layer and to decrease Ru intermediate layer thickness, the IrMn thickness of 4 nm was chosen. However, the pinned effect obtained by such a thin IrMn antiferromagnetic layer is decreased. The exchange coupling field (Hex) measured from the magnetization curve in the easy axis direction was about 10 Oe. I wonder if the oscillatory behavior of the SUL may be caused due to the weak pinned effect and affect the medium noise. So, in this study, the IrMn antiferromagnetic layer thickness was changed, and the relationship between the pinned effect (Hex and magnetic domain) and the recording performance was investigated. 2. E E xperimen tSamples were prepared by using a dc and rf magnetron sputt...

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“…The designed film structure was C (6 nm)/CoPt-TiO 2 (15 nm)/Ru (4 nm)/FeCo (50 nm)/IrMn (10 nm)/Pt (10 nm)/Ta (5 nm)/glass substrate. The B s of an FeCo SUL was 2.45 T. IrMn was used as an fcc underlayer to obtain soft magnetic properties in the FeCo film 2)-4) , and an antiferromagnetic layer to pin the FeCo film 5) . A Pt underlayer is effective in increasing the crystal orientation of the IrMn, which is necessary in order to enhance the exchange coupling energy between the FeCo and the IrMn films.…”

Section: Introductionmentioning

confidence: 99%

Co-Pt Clusters on a Highly Oriented Fe-Co Soft Underlayer in a Co-Pt-TiO2 Perpendicular Medium

Shintaku

2006

J. Magn. Soc. Jpn.

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A granular-type medium with a highly oriented high-Bs Fe-Co soft underlayer (SUL) and a thin Ru intermediate layer of 4 nm was prepared. It displayed low H ch (Hc in the hard axis direction) value of 1.1 Oe in the SUL and high H c of 6.0 kOe in a Co-Pt-TiO2 recording layer. The recording layer in the medium has a novel granular structure, namely, well-isolated clusters composed of 5-15 pieces of small Co-Pt grains 4-7 nm in diameter segregated by TiO 2. The clusters were oval, with an average area of 213 nm 2 . At present, the shape and arrangement of the clusters cannot be controlled successfully.K e y w o r ds: perpendicular recording media, granular film, cluster, Fe-Co soft underlayer, Ru intermediate layer, Ta underlayer.

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CoFe-IrMn exchange-coupled soft underlayers for perpendicular media

Cited by 25 publications

References 11 publications

Giant magnetic domains in amorphous SmCo thin films

Giant magnetic domains in amorphous SmCo thin films

Influence on the Recording Performance due to exchange coupling field of Soft Underlayer in Perpendicular Recording Media

Co-Pt Clusters on a Highly Oriented Fe-Co Soft Underlayer in a Co-Pt-TiO2 Perpendicular Medium

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