Abstract: Formation of magnetic domains in a perpendicularly magnetized medium comprising an underlayer of a soft magnetic layer is prevented by appropriate magnetic domain control in the soft magnetic layer. One method controls magnetic domains of the soft magnetic layer by applying an external magnetic field to the medium. Another method provides a mechanism in the magnetic head for generating a magnetic field to control the magnetic domains of the soft magnetic layer of the medium.

Abstract: A magnetic recording medium having a substrate, an under-layer formed on the substrate, a magnetic layer formed on the substrate and a protective layer formed on the magnetic layer. The magnetic layer comprises Co, Cr and Pt with a thickness being from 10 nm to 22 nm. Further, a coercivity of the magnetic layer is not less than 2000 Oe, and a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe.

Abstract: A magnetic recording medium having a substrate, an under-layer formed on the substrate, a magnetic layer formed on the substrate and a protective layer formed on the magnetic layer. The magnetic layer comprises Co, Cr and Pt with a thickness being from 10 nm to 22 nm. Further, a coercivity of the magnetic layer is not less than 2000 Oe, and a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe.

Abstract: An ferromagnetic thin film is used to provide a magnetic recording medium whose noise is low and whose S/N value is high. The ferromagnetic thin film as the magnetic film of the magnetic recording medium is such that the fluctuation field of magnetic viscosity at 25° C. at the field strength equal to remanence coercivity or coercivity is not less than 15 oersteds and the coercivity is not less than 2000 oersteds.

Abstract: An ferromagnetic thin film is used to provide a magnetic recording medium whose noise is low and whose S/N value is high. The ferromagnetic thin film as the magnetic film of the magnetic recording medium is such that the fluctuation field of magnetic viscosity at 25° C. at the field strength equal to remanence coercivity or coercivity is not less than 15 oersteds and the coercivity is not less than 2000 oersteds.

Abstract: A thin film magnetic recording medium including a magnetic layer having a fluctuation field defined as S/Xirr, where S is magnetic viscosity and Xirr is irreversible susceptibility Xirr. The fluctuation field of the magnetic layer is not less than 15 oersteds.

Abstract: Formation of magnetic domains in a perpendicularly magnetized medium comprising an underlayer of a soft magnetic layer is prevented by appropriate magnetic domain control in the soft magnetic layer. One method controls magnetic domains of the soft magnetic layer by applying an external magnetic field to the medium. Another method provides a mechanism in the magnetic head for generating a magnetic field to control the magnetic domains of the soft magnetic layer of the medium.

Abstract: A thin film magnetic head has a magnetic gap and two magnetic films that hold the magnetic gap therebetween to form a magnetic circuit. At least one of the two magnetic films has a first portion the surface of which is located remote from a throat height=0 point, and exposed to a recording medium and which determines a recording track width, and a second portion not exposed to the recording medium. The cross-sectional area of magnetic path in the second portion is larger than that in the first portion.

Abstract: A thin film magnetic head has a magnetic gap and two magnetic films that hold the magnetic gap therebetween to form a magnetic circuit. At least one of the two magnetic films has a first portion the surface of which is located remote from a throat height=0 point, and exposed to a recording medium and which determines a recording track width, and a second portion not exposed to the recording medium. The cross-sectional area of magnetic path in the second portion is larger than that in the first portion.

Abstract: A ferromagnetic thin film is used to provide a magnetic recording medium whose noise is low and whose S/N is high. The ferromagnetic thin film as the magnetic film of the magnetic recording medium is such that the fluctuation field of magnetic viscosity at 25° C. at the field strength equal to remanence coercivity or coercivity is not less than 15 oersteds and the coercivity is not less than 2000 oersteds.

Abstract: A thin film magnetic recording medium including a magnetic layer having a fluctuation field defined as S/Xirr, where S is magnetic viscosity and Xirr is irreversible susceptibility Xirr. The fluctuation field of the magnetic layer is not less than 15 oersteds.

Abstract: A read-write head is capable of suppressing fluctuation on a reproduced waveform caused by repetition of a writing and reading operation, and is capable suppressing noise appearing in the reproduced waveform just after a writing operation is carried out. The read-write head has an upper magnetic core, an upper shield also serving as an lower magnetic core, a lower shield and a magnetoresistive film arranged between the upper shield and the lower shield. The upper shield has a soft magnetic film having a magnitude of anisotropy field of 5 to 30 Oe, or is a multilayer film composed of a high saturation magnetic flux density film and a negative magneto-striction film. The lower shield has a soft magnetic film having a magnitude of anisotropy field of 5 to 30 Oe.

Abstract: A magnetic disc apparatus capable of noiseless, high-output reproduction is disclosed. A magnetic head including a magnetic domain control structure having an antiferromagnetic film for applying a longitudinally biasing magnetic field to a magneto-sensitive portion of a magneto-resistance effect film, and a magnetic film smaller in spontaneous magnetization than the magneto-resistance effect film, which magnetic film is interposed between the magneto-resistance effect film and the antiferromagnetic film. A magnetic disc apparatus is thus realized which is high in recording density and usable in stable manner within the operating temperature range.

Abstract: In a magnetic recording system including magnetic recording media, a rotation driving unit for driving these magnetic recording media, read/write magnetic heads, driving apparatus for driving these read/write magnetic heads, and a read/write signal processing apparatus, a reading portion of the respective magnetic heads is arranged by a magnetoresistive head. The magnetic recording media are constructed of multi-layered magnetic media having a plurality of magnetic layers fabricated directly, or via underlayers on a non-magnetic disk substrate, and of non-magnetic intermediate layers arranged among these non-magnetic layers.

Abstract: A magnetic disc apparatus has a large recording density of 120 megabits per square inch or more, and defines a relationship among a pole thickness (Pt) of thin-film magnetic heads disposed in the magnetic disc apparatus, and a saturation flux density (Bs) of cores of the heads and a recording wavelength (.lambda.) for the thin film magnetic discs have a coercivity of 1800 Oe or more, wherein a levitation space between the head and the disc is 0.15 .mu.m or less.

Abstract: A magnetic disc apparatus is disclosed, in which a magneto-resistance effect film converts a magnetic signal into an electrical signal by use of the magneto-resistance effect, a pair of electrodes supplies a signal detection current to the magneto-resistance effect film, and a magnetic domain control layer controls the magnetic domain of the magneto-resistance effect film. The magneto-resistance effect film, the electrodes and the magnetic domain control layer constitute a magnetic head of magneto-resistance effect type. An isolation film is formed in a magneto-sensitive portion of the magneto-resistance effect film between the magneto-resistance effect film and the magnetic domain control layer to break the magnetic coupling between the magneto-resistance effect film and the magnetic domain control layer.

Abstract: In a magnetoresistive head, a domain suppressing layer is formed under each of opposite ends of a magnetoresistive film. The domain suppressing layer is composed of a first ferromagnetic film, an antiferromagnetic film and a second ferromagnetic film which are laminated one over another in this order. Since the spin distribution of the antiferromagnetic film is transmitted to the magnetoresistive film via the second ferromagnetic film, a stable longitudinal bias magnetic field can be achieved, irrespective of the degree of contamination of the surface of the ferromagnetic film.

Abstract: In a magnetic disk device having a composite head with an induction type of recording head adjacent a magneto-resistance effect type of reproducing head, a read error relief is provided to relieve read errors caused by Barkhausen Noise or Base Line Shift phenomenon inherent to the magneto-resistance effect type of reproducing head. Upon occurrence of a read error, a re-try function is first executed, and a track offset function is executed for relief of the read error. However, if the read error is not relieved after the offset operation and the re-try operation have been performed a predetermined number of times, then a pseudo write-in and/or read current control operation is performed together with the offset operation and/or re-try operation for a predetermined number of times. The control operation varies the magnetic domain structure in the head magnetic film (MR film).

Abstract: A magnetoresistive head has a substrate (1) and, on the substrate, a magnetoresistive film (40) for converting a magnetic signal into an electric signal by using magnetoresistance effects and a pair of electrodes (60) for causing a signal detection current to flow through the magnetoresistive film. A pair of first domain wall suppressing layers (30) are arranged at opposite end portions of the magnetoresistive film, respectively, to apply a longitudinal magnetic bias to the magnetoresistive film. A second domain wall suppressing layer (45) is also provided for applying a longitudinal magnetic bias, which is weaker compared with the longitudinal magnetic bias applied by the first domain wall suppressing layers, to the magnetoresistive film (40).

Abstract: A magnetoresistance effect type head including a ceramic substrate, a first magnetic film provided on the ceramic substrate, a second magnetic film provided above the first magnetic film, first and second insulating films provided between the first and second magnetic films, a magnetoresistance effect type film provided between the first and second insulating films, a bias film provided between the first and second insulating films in contact with the magnetoresistive film for applying magnetic field to the magnetoresistive film, a first conductive film provided between the first and second insulating films and above the bias film to be nearly as thick as the mean free path of free electrons, and a second conductive film of an electrode structure mutually separated between the first and second insulating films in contact with the first conductive film. The first conductive film is a nickel-chromium film or a chromium film which is resistive to a fluorocarbon-series gas to be used for etching.