Vector magnetisation of recording media: a new method to compensate for demagnetising fields

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

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Selective Sampling and Orientation of Non-Homogeneous Tissues

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100238 ◽

1968 ◽

Vol 26 ◽

pp. 98-99

Author(s):

C. C. Clawson ◽

L. W. Anderson ◽

R. A. Good

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Light Microscopy ◽

Random Sampling ◽

New Method ◽

Microscope Examination ◽

Small Areas ◽

Selective Sampling ◽

Large Numbers ◽

Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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Crystallization of barium hexaferrite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122216 ◽

1992 ◽

Vol 50 (1) ◽

pp. 362-363

Author(s):

Chung-kook Lee ◽

Yolande Berta ◽

Robert F. Speyer

Keyword(s):

Size Distribution ◽

Raw Materials ◽

Barium Hexaferrite ◽

Recording Media ◽

Magnetic Recording Media ◽

Promising Candidate ◽

Crystallization Method ◽

Temperature Heat ◽

High Density Magnetic Recording ◽

Temperature Heat Treatment

Barium hexaferrite (BaFe12O19) is a promising candidate for high density magnetic recording media due to its superior magnetic properties. For particulate recording media, nano-sized single crystalline powders with a narrow size distribution are a primary application requirement. The glass-crystallization method is preferred because of the controllability of crystallization kinetics, hence, particle size and size distribution. A disadvantage of this method is the need to melt raw materials at high temperatures with non-reactive crucibles, e.g. platinum. However, in this work, we have shown that crystal growth of barium hexaferrite occurred during low temperature heat treatment of raw batches.

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Grain separation enhanced magnetic coercivity in Pt/Co multilayers.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151027 ◽

1993 ◽

Vol 51 ◽

pp. 1038-1039 ◽

Cited By ~ 1

Author(s):

G.A. Bertero ◽

R. Sinclair

Keyword(s):

Remanent Magnetization ◽

Strong Influence ◽

Uniaxial Anisotropy ◽

Magnetic Coupling ◽

Recording Media ◽

Magnetic Media ◽

Signal To Noise ◽

Out Of Plane ◽

Longitudinal Recording ◽

The Relationship

Pt/Co multilayers displaying perpendicular (out-of-plane) magnetic anisotropy and 100% perpendicular remanent magnetization are strong candidates as magnetic media for the next generation of magneto-optic recording devices. The magnetic coercivity, Hc, and uniaxial anisotropy energy, Ku, are two important materials parameters, among others, in the quest to achieving higher recording densities with acceptable signal to noise ratios (SNR). The relationship between Ku and Hc in these films is not a simple one since features such as grain boundaries, for example, can have a strong influence on Hc but affect Ku only in a secondary manner. In this regard grain boundary separation provides a way to minimize the grain-to-grain magnetic coupling which is known to result in larger coercivities and improved SNR as has been discussed extensively in the literature for conventional longitudinal recording media.We present here results from the deposition of two Pt/Co/Tb multilayers (A and B) which show significant differences in their coercive fields.

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Structural Investigation of Iron Particles Used for Magnetic Recording Media

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001732 ◽

1980 ◽

Vol 38 ◽

pp. 406-407

Author(s):

Alfred Baltz

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Microscope ◽

Structural Investigation ◽

Magnetic Interaction ◽

Recording Media ◽

Magnetic Recording Media ◽

Recording Medium ◽

Iron Particles ◽

Transmission Electron

As part of a program to develop iron particles for next generation recording disk medium, their structural properties were investigated using transmission electron microscopy and electron diffraction. Iron particles are a more desirable recording medium than iron oxide, the most widely used material in disk manufacturing, because they offer a higher magnetic output and a higher coercive force. The particles were prepared by a method described elsewhere. Because of their strong magnetic interaction, a method had to be developed to separate the particles on the electron microscope grids.

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