Hitachi Global Storage Technologies Netherlands B.v.

Nippon Steel Sumitomo Metal Corporation

Masahiro Osugi

Katsuro Watanabe

Yoshito Isei

Tomoya Kato

Taku Shintani

Nobuo Yoshida

Takayoshi Ohtsu

Kazuhiro Ueda

Hideyuki Takahashi

Shigeo Fujita

Koji Kataoka

A method for measuring flatness of a sheet material in which a light and dark pattern composed by a light portion and a dark portion is projected onto a surface of the sheet material running in a longitudinal direction, a pattern image is acquired by photographing the light and dark pattern by an image pickup device having an image pickup visual field larger than a width of the sheet material, and the flatness of the sheet material is measured by analyzing the acquired pattern image. A staggered pattern is used for the projecting step and for light to be specularly reflected for receipt by the image pickup device. Calculating the flatness also includes steps of setting a shape measurement line, averaging picture element concentrations, calculating a distribution of the concentrations, and calculating the flatness based on surface shape using the distribution.

Method for measuring sheet material flatness and method for producing steel sheet using said measuring method

Measuring sheet material flatness includes projecting a bright and dark pattern made up of bright parts and dark parts onto a sheet material surface travelling in a lengthwise direction, picking up an image of pattern with image pickup device to acquire a pattern image, with the pickup device having a field of view larger than a sheet material width. The acquired pattern image is analyzed, wherein a pattern in which a bright part is disposed at a predetermined set pitch respectively in longitudinal and lateral directions is formed by an LED light at a predetermined pitch respectively in the longitudinal and lateral directions. The pattern is projected onto the surface such that the longitudinal direction of the pattern lies along a lengthwise direction of the sheet material, and the lateral direction of the pattern lies along a width direction of the sheet material.

Method for measuring flatness of sheet material and method for manufacturing steel sheet using the same

According to one embodiment, a CPP magnetoresistive head includes a magnetoresistive film comprising a free layer above a non-magnetic intermediate layer and a fixed layer below the non-magnetic intermediate layer, wherein the magnetoresistive film is between a lower magnetic shield layer and an upper magnetic shield layer. The CPP magnetoresistive head also includes a domain control film on each side of the magnetoresistive film, wherein a sense current flows through the magnetoresistive film between the upper magnetic shield layer and the lower magnetic shield layer. The CPP magnetoresistive head also includes a high heat conductivity layer, and a heat dissipation layer having a high heat conductivity and a low linear expansion coefficient, the heat dissipation layer being disposed at the back in a device height direction of the magnetoresistive film and on each side of the domain control film.

CPP magnetoresistive head

Embodiments in accordance with the present invention reduce the influence of etching damage at junction edge of a magnetoresistive film in the sensor height direction, lower the deterioration of dielectric breakdown voltage between an upper magnetic shield layer and a lower magnetic shield layer and instability of reproducing property resulting from shield process, and maintain electrostatic capacity to a small value in a CPP magnetoresistive head. In an embodiment of a magnetoresistive head of the present invention, length in the sensor height direction of bottom surface of a pinning layer is longer than the length in the sensor height direction of bottom surface of a first ferromagnetic layer. The angle formed by an edge in the sensor height direction of the pinning layer to the surface extended from a bottom surface of a magnetoresistive film is smaller than the angle formed by an edge in the sensor height direction of a second ferromagnetic layer to the surface extended from a bottom surface of the magnetoresistive film. Height of top surface of a sensor height direction refill film is equal to or higher than the top surface of the magnetoresistive film.

Magnetoresistive head and a manufacturing method thereof

A high output magneto-resistive sensor is provided by suppressing leftover resist mask after lift-off and generation of a fence, and by making it easy to remove the redepositions deposited on the side wall in the track width direction or on the side wall in the sensor height direction of the magnetoresistive film. As a means to solve a fence and lift-off leftover of a resist in a process for forming a track and a process for forming a sensor height, a stopper layer is provided on the magnetoresistive film and the stopper layer on the refill film, and performing lift-off by CMP. By using a metallic material which has a small CMP polishing rate for at least the first stopper layer, the magnetoresistive film and the first stopper layer can be etched simultaneously and a pattern formed. As a result, decrease of the height of the resist mask by RIE can be suppressed and lift-off leftover can be prevented.

Growing community of inventors

Tokyo, Japan

Masahiro Osugi