Hitachi, Ltd.

Kenzo Masuda

Hisashi Takano

Moriaki Fuyama

Takashi Kawabe

Masaaki Sano

Shun-ichi Narumi

Yoshiaki Kita

Hisano Yamamoto

Fumio Nakano

Hiroyuki Matsumoto

Masaaki Imamura

Sakae Ohta

Akira Takanashi

Miyuki Kajiki

Makoto Komatsu

Hiroo Sakaba

A magnetic disk apparatus includes a magnetic disk for recording information and a magnetic head which has a reproducing head and a recording head. The reproducing head comprising a lower shield film, a magnetoresistive film, a pair of electrodes and an upper shield, and the recording head comprising an upper magnetic core, a lower magnetic core, and a coil disposed between said upper magnetic core and said lower magnetic core. The upper magnetic core and the lower magnetic core include an electroplated thin film with an average crystal grain size smaller than 500 &angst;, and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Magnetic disk apparatus with magnetic head having upper and lower magnetic cores of an electroplated thin film

A slider having a thin film magnetic head. The thin film magnetic head has an upper magnetic core, a lower magnetic core and a coil disposed between the upper magnetic core and the lower magnetic core. The upper magnetic core and the lower magnetic core is an electroplated thin film with an average crystal grain size smaller than 500 &angst;, and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Thin film magnetic head with electroplated Ni-Fe alloy thin film having small average crystal grain size range

A thin film magnetic head having a first magnetic core, a second magnetic core formed on the first magnetic core, a coil disposed between the first magnetic core and second magnetic core, and a non-magnetic insulator body for separating the first magnetic core, second magnetic core and coil with respect to each other. At least one of the first magnetic core and the second magnetic core includes an electroplated thin film with an average crystal grain size smaller than 500 &angst; and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Thin film magnetic head and assembled construction thereof

A thin film magnetic head and a disk storage system having a magnetic disk and the thin film magnetic head provided on a floating type slider. The thin film magnetic head has an upper magnetic core and a lower magnetic core, wherein the upper magnetic core and the lower magnetic core are made of an electroplated thin film having sufficient average crystal grain size. The upper magnetic core is made of a Ni&mdash;Fe alloy having Ni of 38 to 60 wt % and Fe of 40 to 62 wt %, and the crystal grain size is smaller than 500 &angst;.

Thin film magnetic head with Ni-Fe alloy thin film

A magnetic film having a high saturation magnetic flux density larger than 1.5 T and a resistivity larger than 40 .mu..OMEGA..cndot.cm is fabricated through an electroplating method using (40-60)Ni-Fe and by adding Co, Mo, Cr, B, In, Pd or the like to the (40-60)Ni-Fe. Thereby, it is possible to obtain a recording head capable of performing sufficient recording in a high frequency range and to obtain a disk storage system with a high recording density which has a transfer rate higher than 15 MB/s, a recording frequency higher than 45 MHz and a rotating speed of a magnetic disk higher than 4000 rpm.

This invention relates to a magnetic recording medium wherein the improvement comprises a lubricative film comprising a lubricant having a functional group at one end of the molecule and a lubricant having a functional group at both ends of the molecule. According to the present invention, there are provided a magnetic recording medium having excellent sliding tolerance against the head, reduced adhesiveness and dense surface, and a magnetic storage device using such a recording medium.

Magnetic recording medium having a lubricant film consisting of a

In a magnetic recording medium in which a thin film of a magnetic material is disposed on a surface of a base of a non-magnetic material directly or through an undercoated film, powder of a material substantially the same as that of the non-magnetic base or an undercoated film is disposed directly beneath the magnetic thin film to form dispersed projections on the surface of the magnetic recording medium. Thus, the product has surface projections, and its magnetic thin film has a generally uniform thickness and uniform magnetic properties.

Magnetic recording medium having a thin film magnetic layer formed over

A depletion type MISFET is connected between a power voltage supply line of a transistor logic circuit block and a power source voltage terminal. The gate electrode of the depletion type MISFET is connected to a reference voltage. The transistor logic circuit block has a driving MISFET and a load connected in series between the power voltage supply line and the reference voltage. The load of the transistor logic circuit is similarly constituted by a depletion type MISFET, while the driving MISFET is of enhancement type. The driving MISFET and the load MISFET in the transistor logic circuit block are built-in in a monolithic semiconductor integrated circuit, together with the MISFET for the power voltage supply to the transistor logic circuit. The drain of the power voltage supplying MISFET is connected to the power voltage supply terminal, and is made to have a high breakdown voltage structure so that the breakdown voltage between the drain and the substrate of the power voltage supplying MISFET may be larger than that of the load MISFET.

Integrated circuit having an operation voltage supplying depletion type

A ratioless type MIS logic circuit comprises a logic block including at least one depletion mode FET inherently having a gate-to-source parasitic capacitance and a gate-to-drain parasitic capacitance, an output capacitance, a circuit for precharging the output capacitance and depletion mode clamping FETs connected one with each of the two ends of the logic block, the clamping FETs having their gates connected with a reference potential and the threshold voltage value of the FET in the logic block being larger than those of the clamping FETs.

Ratioless type MIS logic circuit

A read-only memory of lateral type comprising a plurality of information memory circuits connected in parallel with one another across a first line and a second line. In each of the information memory circuits, a first insulated-gate field effect transistor of either the depletion mode or the enhancement mode, selected depending on the information to be stored, is connected in series with a second insulated-gate field effect transistor of enhancement mode. The read-only memory further comprises reading means for reading the mode of the first insulated-gate field effect transistor in each information memory circuits, so that an output signal according to the mode of the first insulated-gate field effect transistor can be read out from the memory by the reading means.

Semiconductor read-only memory

An MIS logic circuit of a ratioless type comprising at least one logic section including one or more MIS FETs and provided with first and second electric energy suppressors which otherwise is fed back from output to input of the logic block through the gate-to-source capacitance and the gate-to-drain capacitance of the MIS FET. The first and second suppressors are connected with the drain and the source of the MIS FET respectively so that they are in series connection.

MIS logic circuit of ratioless type

An MIS switching circuit capable of enduring a high voltage, comprises a switching FET, one or more protective FETs connected in series to the switching FET and a load connected between the drain of the protective FET and a high voltage source, wherein the load is constituted by a series connection of a plurality of FETs.

MIS switching circuit capable of enduring high voltage

A logic circuit of a ratioless structure, wherein a load MOS FET, a drive MOS FET and a pre-discharge MOS FET are connected in series in the described order, a first clock is applied to the pre-discharge MOS FET, a second clock is applied to the load MOS FET, and an input signal is applied to the drive MOS FET while an output signal is derived from the junction between the drive MOS FET and pre-discharge MOS FET.

Logic circuit of ratioless structure

A voltage comparator circuit suitable for a semiconductor integrated circuit device comprises a pair of time constant circuits each of which includes a variable impedance, such as a depletion type MISFET, and a capacitor, the variable impedance being controlled by input voltages which are to be compared with one another and a flip-flop circuit which is stabilized to predetermined values on the basis of the comparison between the time variations of the outputs of the time constant circuits.

Voltage comparator circuit

A frequency-voltage converter using a charge-pump element and a pulse generating circuit stabilized in frequency of the output pulse signal by using the frequency-voltage converter for detecting the deviation or variation of the frequency of the output pulse signal.

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Odawara, Japan

Kenzo Masuda