CoPtCr-SiO/sub 2/ granular media for high-density perpendicular recording

Uwazumi, H.; Enomoto, K.; Sakai, Yuzo; Takenoiri, S.; Oikawa, T.; Watanabe, Shinji

doi:10.1109/tmag.2003.813778

Cited by 96 publications

(41 citation statements)

References 10 publications

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“…CoPtCr-SiO 2 /Ru (a) forms well-segregated CoPtCr fine grains of less than 10 nm diameter surrounded by amorphous SiO 2 as was reported. 1,9,10) On the other hand, CoPtCr-SiO 2 /Pt (b) doesn't form an isolated structure but another network structure composed of CoPtCr particles of 5 nm size. Also, diffraction patterns and their intensity profiles show that diffraction rings of CoPtCr-SiO 2 /Ru are very sharp, whereas those of CoPtCr-SiO 2 /Pt are relatively broad.…”

Section: Resultsmentioning

confidence: 99%

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Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

et al. 2005

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Structural properties of CoPtCr-SiO 2 magnetic recording films grown on Ru or Pt seed layers prepared by UHV-magnetron sputtering were studied by high resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS) and energy filtered transmission electron microscopy (EFTEM). CoPtCr grown on Ru seed layers together with SiO 2 forms a well-isolated structure composed of CoPtCr fine grains of 10 nm diameter surrounded by amorphous SiO 2 , whereas CoPtCr grown on Pt seed layers together with SiO 2 forms a network structure composed of CoPtCr crystal of 5 nm size. These structural features made differences in their magnetic properties. The HRTEM and EFTEM studies revealed that cylindrical crystalline grains composed of CoPtCr and Ru are formed for CoPtCr-SiO 2 /Ru samples, whereas SiO 2 are aggregated around the boundary between relatively large Pt grains and magnetic layers without obstructing the epitaxial growth of CoPtCr on Pt, not resulting in the cylindrical CoPtCr grains. Lattice spacings of CoPtCr grown on Pt with SiO 2 are 0.7% expanded in comparison with CoPtCr grown on Pt without SiO 2 . The EELS studies suggested that Co and Cr atoms are partly oxidized by SiO 2 addition for both samples and Cr atoms are more oxidized for CoPtCr-SiO 2 /Pt samples.

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Section: Resultsmentioning

confidence: 99%

“…It was reported that CoPtCr-SiO 2 / Ru samples formed a well-defined fine grain structure, 1,9,10) but good CoPtCr-SiO 2 /Pt grains have not been reported. It is crucially important for design of recording media with higher order term, K u2 to clarify the growth mechanism of CoPtCrSiO 2 on Ru and that on Pt.…”

Section: Introductionmentioning

confidence: 98%

Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

et al. 2005

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“…In particular, the slope at coercivity of a hysteresis curve, ␣ = ͑4dM / dH͒ Hc , may affect the performance of a magnetic recording medium. 3 Some attention has been paid to the relationship between the parameter ␣ and the magnetic correlation length, L m , as measured by MFM, 10,14 but little work has been done to connect the two with a model to gain information about the real structure of a system.…”

Section: Introductionmentioning

confidence: 99%

Magnetic correlations in nanocomposite FePt:Au and FePt:C films

George

Skomski

Sellmyer

2009

Journal of Applied Physics

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The nanostructure and magnetism of L1 0 -ordered FePt crystallites in matrices of Au and C are investigated as a function of the Au and C contents. Emphasis is on the relation between hysteresis-loop shape, magnetic correlation length, and structural disorder, as relevant to magnetic recording media. The highly ͑001͒ textured thin films are produced by annealing ͓Fe/ Pt/ X͔ n multilayers. The coercivity and the hysteresis-loop slope at coercivity increase and decrease, respectively, with increasing volume fraction of the matrix. The magnetic force microscopy images show that the slope decrease is accompanied by a reduction in the magnetic correlation length. These changes are due to the reduced intergranular exchange coupling, and a simple model describes how interparticle exchange cooperatively increases both the loop slope and the correlation length.

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“…In contrast to its Longitudinal Magnetic Recording (LMR) counterpart, PMR media technologies reported thus far generally relies on a media with small, well-segregated grains connected by amorphous grain boundaries [2]. This grain structure may introduce a surface roughness of several nanometers amplitude [3], which is not negligible in the scale of the required magnetic spacing [4].…”

Section: Introductionmentioning

confidence: 99%

“…The finished media roughness is affected by a large number of variables, and the factors that help produce a smooth media may cause poor magnetic performance. It is not the intention of the paper to discuss the details on how to minimize the roughness of the finished media while maintaining optimum magnetic performance, as this topic was discussed elsewhere [2]. Hence, we will only discuss issues associated with somewhat ''rough'' PMR media, without implying that it is a necessary condition to proper magnetic performance.…”

Section: Introductionmentioning

confidence: 99%

Tribological issues in perpendicular recording media

et al. 2006

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As the hard disk drive industry is transitioning from longitudinal (LMR) to perpendicular (PMR) recording, a new set of reliability challenges had to be overcome. In particular, the magnetic media structure, which relies on well-segregated grains of 6-10 nm diameter, can exhibit a rough structure, with peak-to-mean amplitude of 3-6 nm. In this paper, we will discuss how this topography could affect the overall reliability of the head-disk interface. In the first part, we will illustrate the loss of adequate coverage from the overcoat on PMR media, compared to the smoother LMR media, and we will attempt to quantify the topography in terms of its deviation from a Gaussian height distribution. Particular emphasis will be given to surface outliers and their removal during the burnishing process. The second part will be devoted to the lubricant preferential migration to the grain boundaries, driven by surface tension. It will be shown by an EELS line scan that the lubricant film is indeed thicker in the valleys between the grains, in agreement with surface tension driven redistribution. Finally, we will demonstrate that the Touchdown Height (TDH) of a PMR disk is $0.5 nm higher than its LMR counterpart, owing to its enhanced nano-roughness. Once recognized, these challenges can be overcome through a careful and thorough optimization of the various processing parameters, eventually leading to an overall reliability level equal or better than LMR media.

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CoPtCr-SiO/sub 2/ granular media for high-density perpendicular recording

Cited by 96 publications

References 10 publications

Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

Magnetic correlations in nanocomposite FePt:Au and FePt:C films

Tribological issues in perpendicular recording media

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CoPtCr-SiO/sub 2/ granular media for high-density perpendicular recording

Cited by 96 publications

References 10 publications

Nanostructure of CoPtCr&ndash;SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

Nanostructure of CoPtCr&ndash;SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

Magnetic correlations in nanocomposite FePt:Au and FePt:C films

Tribological issues in perpendicular recording media

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Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media

Nanostructure of CoPtCr–SiO<SUB>2</SUB> Granular Films for Magnetic Recording Media