Hitachi, Ltd.

Hitachi Metals, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Takeo Yamashita

Noriyuki Kumasaka

Shigekazu Otomo

Noritoshi Saito

Mitsuhiro Kudo

Hideo Fujiwara

Yoshihiro Shiroishi

Kazuo Shiiki

Shinji Takayama

Juichi Morikawa

Hiroyuki Suzuki

Yoshibumi Matsuda

Kazumasa Takagi

Masaki Ohura

Sadao Hishiyama

Norikazu Tsumita

Tomoyuki Ohno

Hideo Zama

Hiroshi Ikekame

Teizo Tamura

Kiminari Shinagawa

Nobuo Kobayashi

Tomoo Murata

Toshio Kobayashi

Makoto Saito

Katsuhiro Kuroda

Kazuetsu Yoshida

Ryoichi Nakatani

Takeshi Kimura

Yoshinobu Tarutani

Hiroshi Sakurai

Yokuo Saitoh

Kuninori Imai

Sadanori Nagaike

Yoshihiro Hamakawa

Tsutomu Iimura

Takeshi Tottori

Osamu Inagoya

Takayuki Kobayashi

Yasushi Kitazaki

Takeshi Tajima

Yasuaki Horiuchi

Masashi Hayashi

Shinobu Yabuki

Niroyuki Kumasaka

A duty compensation circuit including a duty detection circuit, a duty adjustment signal generator for generating a control signal from a detected duty, and a duty adjustment circuit, in which the duty detection circuit executes sampling of a clock at sampling timing obtained by causing the clock to be delayed by a variable delay circuit, thereby detecting a duty. Thereby, duty compensation is enabled without preparing a clock higher in operating speed than a clock before compensation.

Duty compensation circuit

In a method of manufacturing a semiconductor device having a first wiring extending in a first direction and a second wiring connected to the first wiring through a connection and extending in a second direction orthogonal to the first direction, the second wiring having a surplus portion projecting from the connection in a direction opposite to the second direction, the first and second wirings are arranged such that a center of the connection is offset in the second direction from a center of the first wiring, and a projecting portion of the first wiring is disposed under the connection.

Semiconductor device with improved wiring arrangement utilizing a projecting portion and a method of manufacturing the same

Devices and methods for generating a magnetic head-specific overshoot current which is combined with an alternating current waveform into a write current used by the magnetic head to store information on a magnetic medium. A processor analyzes the frequency of incoming write data and retrieves from a data table of an overshoot current amplitude and an overshoot current phase. This amplitude and phase information is sent to an overshoot current generator to generate an overshoot current that is responsive to the dynamic impedance properties of a magnetic write head during operation. The data table may have information related to one or many write heads, and the data table may be further subdivided based on additional dynamic characteristics of a write head that may affect the impedance thereof.

Overshoot current phase/amplitude control for hard disk drive write current

A magnetic head has a superconducting quantum interference device having a ring made of a superconductive material including a Josephson junction which links to a magnetic flux generated by a magnetic recording medium, and a magnetic pole for guiding the magnetic flux generated by the magnetic recording medium or the ring made of a superconductive material arranged in parallel to a plane of the magnetic recording medium so that the magnetic flux generated by the magnetic recording medium flows into a through-hole of the ring. A magnetic recording and reproducing apparatus includes such a magnetic head, a winding to which a reproduced signal from the magnetic head is applied and the superconductive ring including the Josephson junction arranged such that the magnetic flux generated by the winding flows thereto.

Magnetic head and magnetic recording and reproducing apparatus using a

A magnetic head has a main magnetic path forming film forming an operation gap, and an auxiliary magnetic path forming film for complementing said main magnetic path forming film. The auxiliary magnetic path forming film is disposed behind the gap depth of said magnetic core and magnetically coupled to the main magnetic path forming film. The main magnetic path forming film has a direction of easy magnetization perpendicular to the direction of depth of the operation gap, while the auxiliary magnetic path forming film has a direction of easy magnetization which coincides with the direction in which said magnetic head opposes the recording medium.

Magnetic head having main and auxiliary magnetic paths

A rotating drum for use in a magnetic recording system. A magnetic head is mounted on the rotating drum, and a magnetic recording medium is wound on the rotating drum, and the rotating drum is rotated so as to read and write signals. Alternatively, the magnetic recording medium is mounted on the rotating drum, and signals are read and written by a magnetic head fixed exteriorly of the rotating drum. The rotating drum has at least one opening or notch in a magnetic recording medium-winding surface thereof. In order to restrain the deformation of the rotating drum during the rotation thereof, the center of gravity of the drum is disposed substantially in registry with the axis of rotation of the drum.

Rotating drum having a center of gravity in registry with an axis of

Disclosed are longitudinal recording media comprising a composite magnetic film formed on a nonmagnetic substrate directly or through a nonmagnetic underlayer, in which all of magnetic thin films constituting the composite magnetic film are magnetically connected, the composite magnetic film has a single in-plane coercivity, and the in-plane coercivity is greater than the in-plane coercivity of a longitudinal magnetically anisotropic magnetic thin film constituting a magnetic thin film nearest to an information recording side among the magnetic thin films constituting the composite film.

Longitudinal magnetic recording media and magnetic memory units

An amorphous magnetic alloy of Co-Nb-Zr system contains Co, Nb and Zr and has a composition which falls, in terms of atomic percent, within the region defined by straight lines connecting, in a ternary composition diagram assuming the total of contents of these three elements to be 100, a point (81% Co, 14% Nb, 5 Zr), a point (88% Co, 9% Nb, 3% Zr), a point (86.5% Co, 12.5% Nb, 1% Zr) and a point (81% Co, 18% Nb, 1% Zr). Disclosed also is a magnetic head having a core at least a part of which is constituted by this amorphous magnetic alloy. This magnetic head, when used in combination with a metal powder tape having a high coercive force, provides a remarkably increased recording-reproducing output.

Amorphous magnetic alloy of Co-Nb-Zr system and magnetic head made from

Disclosed are a magnetic recording medium having a magnetic recording layer formed of a magnetic thin film in which rotational hysteresis integral R.sub.H is within a range of from 0.4 to 1.3 in the measurement by a torque magnetometer, and a continuous magnetic recording medium in which crystal grains are substantially randomly arranged on the upper surface of a magnetic recording layer or on the surface of a non-magnetic subbing layer, and in which each of the crystal grains is made to be in the form of an ellipsoid or needle and to have a length-ways axial ratio of a major axis to a minor axis not smaller than 2, more preferably, not smaller than 4.

Magnetic recording medium

A core burying channel is formed on the outer side surface of an air bearing rail of a floating magnetic head floating on a magnetic disk by an air-flow in a direction perpendicular to a magnetic recording medium travelling direction, and a magnetic core is buried in this core burying channel. This magnetic head can be produced easily by a production method which forms a core burying channel in a non-magnetic block, then deposits a magnetic material to the core burying channel and removes unnecessary portions of the magnetic material.

Floating magnetic head having a magnetic core buried in a channel on an

A tunnel erasing-type magnetic head having a short distance between the gaps, wherein a second core half is sandwiched between the first core half and the third core half, a magnetic gap for recording and reproducing the signals is formed between the first core half and the second core half, and a magnetic gap for erasing is formed between the second core half and the third core half, so that the second core half can be utilized for both recording and reproducing the signals and erasing the signals. The second core half is obtained by forming a thin magnetic film of a high saturation flux density on the base portion composed of a nonmagnetic material that forms the magnetic gap. The first and third core halves are also obtained by forming a thin magnetic film of a high saturation flux density on the magnetic gap surfaces of the base portions to produce performance that can be used for the magnetic recording media having high coercive force. The magnetic head has a short distance between the gaps. When used for a floppy disk apparatus, therefore, there does not develop under-erasing or over-erasing even for small disks, and the effective track width does not decrease, either. This head can be used also as the one in which an ordinary erasing head element and a recording and reproducing head element are combined together.

Magnetic head having short distance between gaps for recording

In a magnetic head employing a metallic ferromagnetic material for portions defining a transducing gap, an oxide film or carbide film and a nonmagnetic metal film are provided in this order on each of track width narrowing grooves, and glass is packed on the nonmagnetic metal film, thereby preventing the deteriorations of magnetic characteristics ascribable to the reaction between the metallic ferromagnetic material and the glass and the production of bubbles ascribable to the reaction between the protective films and the glass, and to achieve the enhancements of recording and reproducing characteristics, the prevention of damages to a recording medium surface, the increase of a head lifetime and the rise of the available percentage of manufacture of the heads. When a glass film is further provided on the nonmagnetic metal film and the glass is packed thereon, more excellent effects are achieved.

Magnetic head having improved track width narrowing grooves

Magnetic head having an integrated recording and playback head and an

A magnetic head includes ferromagnetic amorphous alloy multi-layer films each composed of an alternate lamination of ferromagnetic amorphous alloy layers and magnetic spacer layers. The thickness of each ferromagnetic amorphous alloy layer is of 1 .mu.m to 10 .mu.m. The thickness of each magnetic spacer layer is of 0.01 .mu.m to 0.2 .mu.m. The ferromagnetic amorphous alloy multi-layer films constitute at least parts of the head core.

Magnetic head having ferromagnetic amorphous alloy multi-layered film

Growing community of inventors

Tachikawa, Japan

Takeo Yamashita