Hitachi, Ltd.

Osaka University

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Global Storage Technologies

Akita University

Ryoichi Nakatani

Toshio Kobayashi

Hisashi Takano

Masahiro Kitada

Hideo Tanabe

Noboru Shimizu

Naoki Koyama

Isamu Yuito

Masaaki Futamoto

Yoshibumi Matsuda

Mikio Suzuki

Kazuo Shiiki

Kyo Akagi

Takeshi Nakao

Yoshinori Miyamura

Fumio Kugiya

Eijin Moriwaki

Hirotsugu Fukuoka

Takayuki Munemoto

Tokuho Takagaki

Noriyuki Kumasaka

Shigekazu Otomo

Toshihiko Sato

Nobuyuki Inaba

Yasushi Endo

Masahiko Yamamoto

Yoshio Suzuki

Hitoshi Nakamura

Yoji Maruyama

Noritoshi Saito

Yuzuru Hosoe

Takeo Yamashita

Nagatugu Koiso

Hitoshi Saito

Satoru Yoshimura

Masahiko Fujishiro

Yukinori Kinoshita

Hikaru Nomura

A magnetic field measuring device including: a vibrational probe unit having a probe that includes one or more material(s) whose intensity of magnetization is proportionate to an external magnetic field, a mechanical vibration source for the probe; a vibration detector detecting a vibration frequency and amplitude of the probe; an alternating-current magnetic field generator applying to the probe an alternating-current magnetic field; a direct-current external magnetic field generator applying a direct-current external magnetic field to the probe; a frequency modulation detector detecting frequency modulation occurring to the mechanical vibration of the probe; a direct-current external magnetic field controller adjusting the intensity of the direct-current external magnetic field applied to the probe; and a direct-current magnetic field determination unit determining a value of the direct-current magnetic field originating from a specimen.

Magnetic field value measuring device and method for measuring magnetic field value

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Magnetic apparatus with perpendicular recording medium and head having multilayered reproducing element using tunneling effect

Method for manufacturing magnetic head device

A plurality of magnetic memories with respective ring-shaped magnetic layers therein are prepared. The magnetic layers have respective notches formed by partially cutting out the peripheries thereof in circular arc shape. The magnetic memories are arranged in plane so that the surfaces of the notches are parallel to one another.

Magnetic memory array, method for recording in a magnetic memory array and method for reading out from a magnetic memory array

A magnetic memory is composed of a ring-shaped magnetic layer that includes a notch having a circular arc shape. The notch is formed by partially cutting out the periphery of the ring-shaped magnetic layer. A ratio h/Hfor the magnetic layer is set to be equal to or greater than 0.01 where 'h' is the height of the notch and 'H' is the outer diameter of the magnetic layer.

Magnetic memory element with vortex magnetization to control magnetization rotation and prevent leakage of magnetic flux

A magnetic memory includes a magnetic substance composed of a disc-shaped first magnetic layer and a ring-shaped second magnetic layer which is formed on the first magnetic layer.

Magnetic memory, magnetic memory array, method for fabricating a magnetic memory, method for recording in a magnetic memory and method for reading out from a magnetic memory

The present application provides a magneto-resistive element excellent in symmetry of playback waveforms. The basic construction of the present application is as follows. That is, a magnetic layer an insulating layer and a magnetic layer are laminated; a power supply for applying a voltage between two magnetic layers is provided; an anti-ferromagnetic layer 16 is laminated on the magnetic layer direction of which magnetization is substantially parallel or counter-parallel with a detecting direction of an external magnetic field, and when the external magnetic field is not present, a power supply for causing a current to flow in a non-magnetic metal layer and in an inner direction of a layer surface thereof is provided so that a direction of magnetization of the magnetic layer is substantially at right angles to the detecting direction of the external magnetic field; and there is provided a signal detector for detecting a change of current tunneling through an insulating layer when the direction of magnetization of the magnetic layer is changed by the external magnetic field.

Magnetic head with tunneling multi-layer magnetoresistive element biased by current controller

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Magnetic head with conductors formed on endlayers of a multilayer film having magnetic layer coercive force difference

The present application provides a magneto-resistive element excellent in symmetry of playback waveforms. The basic construction of the present application is as follows. That is, a magnetic layer , an insulating layer , and a magnetic layer are laminated; a power supply for applying a voltage between two magnetic layers is provided; an anti-ferromagnetic layer is laminated on the magnetic layer , direction of which magnetization is substantially parallel or counter-parallel with a detecting direction of an external magnetic field, and when the external magnetic field is not present, a power supply for causing a current to flow in a non-magnetic metal layer and in an inner direction of a layer surface thereof is provided so that a direction of magnetization of the magnetic layer is substantially at right angles to the detecting direction of the external magnetic field; and there is provided a signal detector for detecting a change of current tunneling through an insulating layer when the direction of magnetization of the magnetic layer is changed by the external magnetic field.

Magnetic recording apparatus with tunneling magnetoresistive element biased by current controller

A magnetic sensor is constructed to be capable of detecting the change of tunnel current due to co-tunneling effect at a high S/N ratio by using a tunneling magneto-resistive element having a first magnetic layer of a soft magnetic material formed on a flat substrate, first and second tunnel barrier layers formed on the first magnetic layer, magnetic particles of a ferromagnetic material provided between the first and second tunnel barrier layers, and a second magnetic layer of a soft magnetic material formed on the second tunnel barrier layer so as to create tunneling junctions.

Magnetic device

Magnetic disk apparatus including magnetic head having multilayered reproducing element using tunneling effect

Magnetic head with tunneling magnetoresistive element biased by current controller

It is the object of the invention to provide a magnetic head and a magnetic storage apparatus using the magnetic head provided with a signal reproducing means which is capable of using the same signal processing circuit as used for the conventional longitudinal magnetization film type recording medium even when a perpendicular magnetization film type recording medium is used. Because the present invention renders the reproducing signal generated from a perpendicular magnetization film Gaussian shaped (Lorentzian pulse), the same signal processing circuit as used for the conventional longitudinal magnetization film type recording medium can be used. To accomplish this object, in the reproducing means which is the component of the information reproducing component of the magnetic head, the first spin valve element and the second valve element are piled up, the magnetization direction of pinned layers of both elements is prescribed so as to be antiparallel each other, and lead electrodes of both elements are connected so as to be common. When two spin valve elements are piled up to compose a reproducing means, the first spin valve element is structured so as to have an Ru film between the first ferromagnetic film and the second ferromagnetic film and so as to have a Cu film between the second ferromagnetic film and the third ferromagnetic film, and the second spin valve element is structured so as to have a Cu film between the fourth ferromagnetic film and the fifth ferromagnetic film. These two elements are piled up with interposition of a desired spacer film adjacently.

Magnetic head and magnetic storage apparatus using the same

Tunneling magnetoresistive element using a bias magnetic field

Growing community of inventors

Akigawa, Japan

Ryoichi Nakatani