A magnetic evaluation of interaction and noise characteristics of CoNiCr thin films

Mayo, P.I.; O’Grady, K.; Kelly, P. E.; Cambridge, J.; Sanders, I.L.; Yogi, T.; Chantrell, R.W.

doi:10.1063/1.348263

Cited by 130 publications

(57 citation statements)

References 8 publications

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“…Fig. 10 shows the curves [6] for films with and without a soft underlayer. From these data, it is clear that the soft underlayer significantly increases the intergranular coupling as shown by the significant increase in the slope of the curves in the switching region.…”

Section: Effect Of a Soft Underlayer On Coupling In Longitudinal Fmentioning

confidence: 99%

Magnetic characterization of perpendicular recording media

Holloway

Laidler

et al. 2002

IEEE Trans. Magn.

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Article:Wu, J. orcid.org/0000-0003-0007-4328, O'Grady, K., Khizroev, S. et ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract-In this paper, we describe techniques for the magnetic characterization of perpendicular recording media. Such measurements made using traditional techniques, such as the vibrating sample magnetometry (VSM) and alternating gradient force magnetometer (AGFM), have to be corrected for the sample shape demagnetizing factor, which is often found not to be equal to 4 . For measurements other than the simple hysteresis loop, such as remanence curves, this correction must be carried out in real time and we describe the method by which this can be achieved and the process for achieving the correct demagnetization of perpendicular films prior to measurements of the isothermal remanent magnetization curve. A further complication is that real perpendicular media have a soft underlayer beneath the recording layer, which swamps and confuses signals from instruments such as VSM or AGFM. Hence, we describe the construction and use of a magnetooptical Kerr effect magnetometer, which does not penetrate significantly into the soft layer and enables the perpendicular layer to be measured independently. We describe the properties of a traditional alloy perpendicular medium and a Co-Pd multilayer system, which in the latter case exhibits multiple switching behavior. We also address the issue of the effect of the soft underlayer on the coupling in similar longitudinal films and find that the presence of the underlayer induces significant additional coupling effects that may well give rise to an increase in noise in recorded signals.

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Section: Effect Of a Soft Underlayer On Coupling In Longitudinal Fmentioning

confidence: 99%

Magnetic characterization of perpendicular recording media

Holloway

Laidler

et al. 2002

IEEE Trans. Magn.

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“…It is considered [6,7] that the strength of intergranular exchange coupling is the main factor to determine the magnitude of AM AM max with increasing Pt suggests the increase of the strength of intergranular exchange coupling. On the contrary, in CoNiCrPt media, ~ drastically decreases with increasing Pt content.…”

Section: Lntergranular Coupling Characterized By Am Plotmentioning

confidence: 99%

Experimental Characterization of Intergranular Exchange Coupling in CoCrTaPt and CoNiCrPt Thin Film Media

et al. 1994

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Abstract-Quantitative characterizations of magnetic anisotropy of grains and intergranular coupling were carried out in (C0 86 Cr 12 Ta:0100-XPt x (X= 1-9) and (Co 62.sNi 30 Cr 75) lOO-XPtX (X=O-16) thin film media, by magnetic torque and AM analyses. In both materials, magnetocrystalline anisotropy field of grains Hkgrain increases twice as large as those of X=O with increasing X to about 9at%, which plays a main role in increasing He-However, Hc/Hkgrain decreases with increasing X in both media. In CoCrTaPt media, the decrement of Hc/H kgrain is found to be mainly caused by the increment of intergranular exchange coupling. In CoNiCrPt media, it is suggested that the change of c-axes directions from in plane to normal mainly causes the decrement in Hc/Hkgrain. Furthermore, to examine the effect of intergranular coupling on magnetic properties by means of 6M plot, it is clarified that the difference of H kgrain should be taken into account.

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“…In Ref. 3, a correlation was established between the maximum value of d(␦m)/dH and the integrated noise power from the media. This paper reports the magnetic and structural properties of Cr/SmCo x /Cr films on Si ͑100͒ substrates, having variable Cr underlayer thickness and texture.…”

Section: ͑2͒mentioning

confidence: 99%

“…2 Furthermore, the Cr underlayer has an important influence on the intergranular exchange and magnetostatic coupling in the films. Recent works 3 have used remanence curves to characterize the interparticle interactions in recording media and have established a correlation between the recording noise and parameters derived from the remanence curves.…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties and underlayer thickness in SmCo/Cr films

Romero

Cornejo

Rhen

et al. 2000

Journal of Applied Physics

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SmCo films with a Cr underlayer have been investigated as potentially attractive candidates for high density recording media. Magnetron sputtering was used here to produce Cr/SmCo x /Cr films on Si ͑100͒ substrates. The magnetic films were deposited at a substrate temperature of 350°C and an Ar pressure of 5 mTorr. Cr underlayers were deposited both at 25°C and at 350°C and exhibited different textures. Layer thicknesses were evaluated using Rutherford backscattering spectroscopy, while SmCo grain size and underlayer texture were determined from a Rietveld analysis of x-ray diffraction data. The magnetic properties were measured with a vibrating sample magnetometer. The resulting films had in-plane coercivities in the range 4-8 kOe. For a SmCo layer with a thickness of 200 nm, the Cr underlayer thickness was varied in the range 75-300 nm to study its effect on intergranular coupling in the films. For thermally demagnetized samples, both magnetizing and demagnetizing remanence curves were measured and used to evaluate switching field distributions and ␦m plots. The underlayer texture was found to affect magnetic properties more strongly than underlayer thickness.

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A magnetic evaluation of interaction and noise characteristics of CoNiCr thin films

Cited by 130 publications

References 8 publications

Magnetic characterization of perpendicular recording media

Magnetic characterization of perpendicular recording media

Experimental Characterization of Intergranular Exchange Coupling in CoCrTaPt and CoNiCrPt Thin Film Media

Magnetic properties and underlayer thickness in SmCo/Cr films

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