Fujitsu Corporation

Yoshihiko Seyama

Yutaka Shimizu

Atsushi Tanaka

Keiichi Nagasaka

Hitoshi Kanai

Reiko Kondo

Hirotaka Oshima

Shin Eguchi

Hitoshi Kishi

Junya Ikeda

Takahiko Sugawara

Shinya Iijima

In a magnetic sensor, a lower terminal layer, a magnetosensitive layer, and a cover film are simultaneously patterned into substantially the same size. The opposing surface of the lower terminal layer, which opposes the magnetosensitive film is substantially superposed on one opposing surface of the magnetosensitive film. The opposing surface of the upper terminal layer, which opposes the magnetosensitive film is formed into a shape smaller than and included in the other opposing surface of the magnetosensitive film. This implements a magnetic sensor which uses a CPP structure and is yet readily processible and which includes a substantially accurate fine CPP structure in accordance with a desired output.

Manufacturing method of a magnetic sensor

A CPP magnetoresistive effect element includes a free magnetization layer, a fixed magnetization layer, and a plurality of conductive non-magnetic intermediate layers formed between the free magnetization layer and the fixed magnetization layer. An insulating layer and a magnetic layer including magnetic atoms are provided between any two of the non-magnetic intermediate layers.

CPP magnetoresistive effect element and magnetic storage device having a CPP magnetoresistive effect element

A magnetoresistive element that detects a change of magnetoresistance by giving a sense current in the thickness direction of a magnetoresistive effect film including at least a base layer, a free layer, a non-magnetic layer, a pinned layer, a pinning layer, and a protection layer, includes a granular structure layer that includes conductive particles and an insulating matrix material in the form of a thin film containing the conductive particles in a dispersed state and having a smaller thickness than the particle diameter of the conductive particles, the granular structure layer being interposed between at least two adjacent layers among the base layer, the free layer, the non-magnetic layer, the pinned layer, the pinning layer, and the protection layer.

Magnetoresistive element

Magnetic sensor and method of manufacturing the same

A magnetoresistive sensor including the following layers, in order: a first conductor layer; a first antiferromagnetic layer; a first pinned ferromagnetic layer; a first nonmagnetic intermediate layer; a free ferromagnetic layer; a second nonmagnetic intermediate layer; a second pinned ferromagnetic layer; a second antiferromagnetic layer; and a second conductor layer. Alternatively, the magnetoresistive sensor may include the following layers, in order: a first conductor layer; a first free ferromagnetic layer; a first nonmagnetic intermediate layer; a first pinned ferromagnetic layer; an antiferromagnetic layer; a second pinned ferromagnetic layer; a second nonmagnetic intermediate layer; a second free ferromagnetic layer; and a second conductor layer.

Magnetoresistive sensor

Disclosed herein is a spin valve magnetoresistive sensor including a first conductor layer, a free ferromagnetic layer provided on the first conductor layer, a nonmagnetic intermediate layer provided on the free ferromagnetic layer, a pinned ferromagnetic layer provided on the nonmagnetic intermediate layer, an antiferromagnetic layer provided on the pinned ferromagnetic layer, and a second conductor layer provided on the antiferromagnetic layer. At least one of the free ferromagnetic layer and the pinned ferromagnetic layer has a thickness larger than that providing a maximum resistance change rate or resistance change amount in the case of passing a current in an in-plane direction of the at least one layer. That is, the thickness of at least one of the free ferromagnetic layer and the pinned ferromagnetic layer falls in the range of 3 nm to 12 nm.

Spin valve magnetoresistive sensor having CPP structure

A magnetoresistive device includes a laminated film, and a mechanism for applying sense current in a direction of lamination in the laminated film, wherein the laminated film includes a first ferromagnetic layer having a substantially fixed direction of magnetization, a second ferromagnetic layer having a freely variable direction of magnetization according to an external magnetic field, the second ferromagnetic layer including a non-magnetic metal layer, and two or more ferromagnetic metal layers separated from each other by the non-magnetic metal layer in the direction of lamination, and a non-magnetic intermediate layer that separates the first and second ferromagnetic layer from each other.

CPP GMR free layer having ferromagnetic layers with parallel magnetization separated by non-magnetic layer

A magnetic sensor having such a structure that a hard layer for controlling the magnetic domain formed of a conductive hard magnetic material, and a magnetic sensor layer, are at least partially in direct contact with each other, and current flows in the direction wherein at least a main component of current is perpendicular to the surface of the magnetic sensor layer. The current flowing in the magnetic sensor layer and the hard layer is controlled by changing the resistivity of the hard layer. The magnetic sensor is used as a magnetic read head in a magnetic recording apparatus such as magnetic disk apparatus.

Magnetic sensor, magnetic head and magnetic recording apparatus

A current perpendicular-to-the-plane (CPP) structure spin valve magnetoresistive (MR) transducer includes an insulating layer. A pinned or free ferromagnetic layer serves to space or isolate the insulating layer from a non-magnetic spacer layer interposed between the pinned and free ferromagnetic layers. The sensing current is allowed to penetrate through the insulating layer. Fine pin-holes generally formed in the insulating layer are supposed to enable migration of electrons through the insulating layer. Similar to the situation in which the sensing current is allowed to flow through a reduced sectional area, a larger variation can be obtained in response to the inversion of the magnetization in the free ferromagnetic layer. The spin valve MR transducer is expected to greatly contribute to realization of a still higher recording density. Moreover, the spin valve MR transducer is also expected to exhibit an electric resistance approximately equal to a tenth part of that of a well-known tunnel junction magnetoresistive (TMR) element. Accordingly, a thermal noise can significantly be suppressed in the spin valve MR transducer as compared with the TMR element.

Current perpendicular-to-the-plane structure spin valve magnetoresistive head

A magnetic sensor utilizing a giant magnetoresistance (GMR) effect, wherein an insulation layer with a contact hole is formed on a lower terminal layer, a GMR layer is formed thereover on the region including the entire contact hole and at least the surrounding insulation layer, and an upper terminal layer is formed thereover. The sensor offers several advantages in that it is easy to manufacture and is compact, and has a high degree of resistance change.

Magnetic sensor having a GMR layer

A raw material for injection molding comprising a metal powder or a ceramic powder, and a binder containing at least two types of resins, obtained by coating or encapsulating the metal powder or ceramic powder particles with a resin insoluble in a predetermined solvent and having a high softening temperature, and subsequently kneading the resultant powder and a resin soluble in the solvent and having a low softening temperature.

Raw material for injection molding

A process for producing a sintered body, comprising inserting a separately formed first molded article in a mold for injection molding, injection-molding a material identical to or different from that of the first molded article in the mold so that the injected material and the first molded article form together a second molded article, degreasing the second molded article, sintering the degreased article thereby obtaining a sintered body having a difference in shrinkage during the sintering between the first molded article and the injection molded portion of the second molded article other than the first molded article portion being 5% or less. The resulting sintered body is useful as a magnet base.

Process for producing sintered body and magnet base

A magnet base, having a flux density equal to that of an Fe-50%Co alloy and an input current response equal to that of an Fe--Si alloy, is used as a component of the magnetic circuit employed for a printing head of a wire dot printer, the magnetic circuit further having by-pass and armature components. The material of the magnetic base is an Fe-50% Co alloy and the base has an end face which is perpendicular to the magnetic circuit of the printing head. A layer, of a material selected from the class consisting of metals and metal alloys which function to increase the specific resistance of a magnet bases of an Fe-50% Co alloy, is formed on the end face of the magnet base and reduces eddy current loss therein, particularly at high frequency energization of the magnetic circuit, further serving to increase the input current response. The magnet base is formed by kneading soft magnetic powder, comprising the Fe-50% Co alloy, and a binder to form a kneaded mixture which is injection molded into the desired shape of the magnet base, heated for removing the binder and producing a degreased structure, and which then is sintered. The sintered base then is annealed and the layer formed on the end surface by vacuum deposition; alternatively, the layer may be vacuum deposited on the end surface of the sintered magnetic base and the composite structure then annealed.

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Kawasaki, Japan

Yoshihiko Seyama