Patent number 8786986 is assigned to
The following quote was obtained by the news editors from the background information supplied by the inventors: "Disk drives are known in the art that use various kinds of disks, such as: optical disks, magneto-optical disks, flexible magnetic-recording disks, and similar disk data-storage devices. In particular, hard-disk drives (HDDs) have been widely used as indispensable data-storage devices for current computer systems. Moreover, HDDs have found widespread application to motion picture recording and reproducing apparatuses, car navigation systems, cellular phones, and similar devices, in addition to the computers, because of their outstanding information-storage characteristics.
"A HDD includes a magnetic-recording disk and a head-slider; data on the magnetic-recording disk are read and written with the head-slider. To increase recording information-storage capacity per unit area on the magnetic-recording disk, areal density of recorded information is increased. However, reduction in recording bit length raises an issue that the areal density cannot be increased beyond a limiting value, known by the term of art, 'superparamagnetic limit,' determined by thermal fluctuation in magnetization of the recording medium. Generally, the effects of the thermal fluctuation increase as the value of KuV/kT is smaller, where: Ku is a magnetic anisotropy constant of the recording medium; V is a minimum unit volume for magnetization in the recording medium; k is a Boltzmann constant; and, T is absolute temperature. Accordingly, Ku or V is increased so as to reduce the effect of the thermal fluctuation in the recording medium of the magnetic-recording disk.
"In order to address this issue, as is known in the art, a perpendicular-magnetic-recording (PMR) method has been developed that writes with a magnetic signal perpendicularly on a bilayer PMR medium including a soft-magnetic underlayer with a probe-pole write head. This method can apply a stronger magnetic-recording field to the magnetic-recording disk. Therefore, a recording layer of a magnetic-recording disk with a large magnetic anisotropy constant, Ku, can be used. Moreover, in a magnetic-recording disk in the PMR method, an increase in V may be provided by growing magnetic particles in the film thickness direction while maintaining the magnetic particle diameter on the medium surface small, or maintaining the bit length small.
"Another parameter affecting the areal density of recorded information on the PMR medium is the spacing between the thin-film magnetic-recording head and the recording surface of the magnetic-recording disk, known in the art as, 'fly height,' of the thin-film magnetic-recording head in proximity with a recording surface of the magnetic-recording disk. The fly height may be controlled by a technique known in the art as, 'thermal-fly-height control,' or 'TFC'.
"Engineers and scientists engaged in HDD manufacturing and development are interested in the design of thin-film magnetic-recording heads in HDDs that increase areal density to meet the rising demands of the marketplace for increased data-storage capacity, performance, and reliability."
In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "Embodiments of the present invention include a head-slider. The head-slider includes a slider, and a thin-film magnetic-recording head formed by stacking a plurality of layers on the slider. The thin-film magnetic-recording head includes: a read element for reading data; a write element for writing data; a non-magnetic insulating protective layer disposed around the read element and the write element; a resist disposed at a position further away from an air-bearing surface than the read element; and, a hard-material member including a material selected from the group consisting of silicon carbide (SiC) and tungsten (W), which is disposed at a position further away from the air-bearing surface than the read element and the write element. An end of the resist on an air-bearing surface side overlaps the write element when viewed in a stacking direction of the thin-film magnetic-recording head. An end of the hard-material member on the air-bearing surface side overlaps the write element when viewed in a stacking direction of the thin-film magnetic-recording head. A ratio of a distance from the air-bearing surface to a deepest end of the hard-material member to a distance from the air-bearing surface to a deepest end of the resist is at least 0.9."
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