Magnetic measurement of interaction effects in CoNiCr and CoPtCr thin film media

Mayo, P.I.; O'Grady, K.; Chantrell, R.W.; Cambridge, J.; Sanders, I.L.; Yogi, T.; Howard, J. K.

doi:10.1016/0304-8853(91)90221-u

Cited by 83 publications

(30 citation statements)

References 13 publications

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“…Such a projection is equivalent to integrating along H, leading to ‫ץ͑͐‬ 2 M͑H R , H͒ / ‫ץ‬H R ‫ץ‬H͒dH = dM͑H R ͒ / dH R , which also characterizes the switching field distribution ͑SFD͒. Conventionally, the SFD information is determined from the dc-demagnetization ͑DCD͒ remanence curve, 20,21 by taking the full width at half maximum of the dM r ͑H R ͒ / dH R curve, where M r ͑H R ͒ is the zero-field magnetization along a FORC with reversal field H R . Thus, the FORC projection and the DCD methods are similar.…”

mentioning

confidence: 99%

Anisotropy dependence of irreversible switching in Fe∕SmCo and FeNi∕FePt exchange spring magnet films

Davies

Hellwig

Fullerton

et al. 2005

Applied Physics Letters

140

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Magnetization reversal in exchange-spring magnet films has been investigated by a first-order reversal curve ͑FORC͒ technique and vector magnetometry. In Fe/epitaxial-SmCo films, the reversal proceeds by a reversible rotation of the Fe soft layer, followed by an irreversible switching of the SmCo hard layer. The switching fields are clearly manifested by separate steps in both longitudinal and transverse hysteresis loops, as well as sharp boundaries in the FORC distribution. In FeNi/ polycrystalline-FePt films, particularly with thin FeNi, the switching fields are masked by the smooth and step-free major loop. However, the FORC diagram still displays a distinct onset of irreversible switching and transverse hysteresis loops exhibit a pair of peaks, whose amplitude is larger than the maximum possible contribution from the FeNi layer alone. This suggests that the FeNi and FePt layers reverse in a continuous process via a vertical spiral. The successive versus continuous rotation of the soft/hard layer system is primarily due to the different crystal structure of the hard layer, which results in different anisotropies.

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mentioning

confidence: 99%

Anisotropy dependence of irreversible switching in Fe∕SmCo and FeNi∕FePt exchange spring magnet films

Davies

Hellwig

Fullerton

et al. 2005

Applied Physics Letters

140

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“…Computer simulations [10,11] as well as experiments [5,12] indicate a close relation between the exchange and noise in longitudinal recording media with the noise becoming larger as the interaction becomes stronger. However, since in perpendicular recording media no free charges are generated within bit transitions the recording performance will be less affected by strong exchange interactions as compared to longitudinal recording media.…”

Section: -------------------mentioning

confidence: 85%

Coercivity Mechanism in Data Storage Media

Kisker

Suzuki

1996

J. Magn. Soc. Jpn.

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-The coercivity mechanism in polycrystalline CoCrPt thin films, ColPt multilayer systems and in amorphous TbFeCo thin films was studied by analyzing the field and time dependencies of the magnetization. The initial susceptibility Xo and the apparent coercivity as deduced from measuring minor loops indicate a much larger contribution of reversible magnetization processes and a much broader switching field distribution in the polycrystalline CoCrPt magnetic recording medium as compared to the perpendicular magneto-optic ColPt and TbFeCo media. The magnetic interactions in the media have been determined by oM measurements yielding the strongest interactions in the amorphous TbFeCo films and the smallest in the polycrystalline CoCrPt films. Analyzing the relaxation behavior of the magnetization the Barkhausen volume was estimated for all the three media and compared with the results from microstructure analysis by TEM and AFM.

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“…Measurements of the variation of remanence with angle were made at different points along the tape using a VSM with maximum field of 10 kOe. The SFD for each sample was determined from the DCD curve measured on a PMC AGFM with a maximum field of 10 kOe by differentiation and normalization of the DCD curve [7]. The physical orientation was determined using a JEOL-1200Ex TEM.…”

Section: Methodsmentioning

confidence: 99%