Tdk Corporation

Osamu Harakawa

Makoto Kameno

Takato Fukui

Yuichiro Yamaji

Tamon Kasajima

Taiju Akushichi

Koji Kuroki

Masaaki Kaneko

Kazuaki Takanuki

Ikuhito Onodera

To facilitate a change in the number and layout of magnetic field detection devices to be arranged in an array. A magnetic field detection device includes a cancel coil wound around a bobbin, a cover member fixed to the bobbin and covering the cancel coil in a direction perpendicular to the axial direction of the cancel coil, and magnetic sensors fixed to the bobbin or cover member. The cover member has side surfaces and extending in the z-direction and positioned on mutually opposite sides. The side surfaces have first and second engagement portions, respectively, and the first engagement portion has a shape engageable with the shape of the second engagement portion. This makes it possible to arrange a desired number of the magnetic field detection devices.

Magnetic field detection device and magnetic field detection device array

To reduce the number of components and simplify the circuit configuration in a magnetic field detection device capable of detecting a weak magnetic field without using a shield room. A magnetic field detection device includes a cancel coil wound around a winding core part of a bobbin, magnetic sensors fixed to mutually different positions of the bobbin, and a feedback circuit that makes a cancel current flow in the cancel coil according to an output signal from the magnetic sensor to cancel the environmental magnetic field in a cancel space. Since the cancel coil is used in common for the magnetic sensors, it is possible to reduce the number of components to be used and to simplify the circuit configuration.

To increase, in a magnetic sensor having a magnetoresistive strip and a ferromagnetic film, a magnetic bias to be applied to a magnetoresistive element by magnetically coupling the magnetoresistive strip and ferromagnetic film. A magnetic sensorincludes a magnetoresistive strip S, an insulating filmthat covers the magnetoresistive strip S, and ferromagnetic films Mand Mformed on the insulating filmand arranged in the x-direction through a magnetic gap G extending in the y-direction. The ferromagnetic films Mand Moverlap a plurality of hard magnetic members H through the insulating film. This allows two adjacent hard magnetic members H to be magnetically coupled through the ferromagnetic films Mand M. This makes it possible to increase the magnetic bias to be applied to a magnetoresistive element R without involving an increase in the size of the hard magnetic member H.

Magnetic sensor

To provide a method of, and a device for, detecting smear of a magnetic head, in which detection of smear development before magnetic head assembly is made possible by measuring electrical resistance values between pads and shields of a slider that is integrated with a head main body portion, and in addition, throughput increases. The method of detecting smear of a magnetic head includes measuring electrical resistance values between pads of a slider having an integrated head main body portion, or between the pads and a conductor portion that is connected to a shield of the head main body portion to thereby detect smear development.

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Tokyo, Japan

Osamu Harakawa