Denso Corporation

Tohoku University

Takamoto Furuichi

Toshifumi Yano

Kenichi Ao

Hisanori Yokura

Yasuo Ando

Mikihiko Oogane

Takafumi Nakano

Ryuichiro Abe

A magnetic sensor includes: a substrate; and first and second magnetoresistive devices on one surface of the substrate. Each of the first and second magnetoresistive devices includes: a fixed layer having an easy magnetization axis perpendicular to the one surface and having a fixed magnetization direction; a free layer having a variable magnetization direction; and an intermediate layer made of a non-magnetic material and arranged between the fixed layer and the free layer. The fixed layer includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer arranged between the first ferromagnetic layer and the second ferromagnetic layer.

Magnetic sensor and method for manufacturing said magnetic sensor

In a magnetic sensor, a pinned layer covers a wiring layer on a side opposite to a substrate with respect to the wiring layer and includes a bent portion having a bent shape in cross section. Free layers are arranged on a side opposite to the substrate with respect to the pinned layer. The size of the free layers in a planar direction is set to a size smaller than the size of the pinned layer in the planar direction. A magnetic field leaking from the pinned layer may form a closed loop adjacent to the substrate, that is, on a side opposite to the free layers with respect to the substrate. Therefore, influence of the magnetic field leaking from the pinned layer on the free layers can be restricted.

Magnetic sensor

A magnetic sensor includes a magnetization fixed layer, a magnetic field detecting layer, and an intermediate layer. The magnetization fixed layer is formed into a thin-film shape, and a magnetization direction of the magnetization fixed layer is fixed in a direction parallel to an in-plane direction. A magnetization direction of the magnetic field detecting layer changes depending on an external magnetic field. The intermediate layer is disposed between the magnetization fixed layer and the magnetic field detecting layer, and a resistance value of the intermediate layer changes depending on an angle between the magnetization direction of the magnetization fixed layer and the magnetization direction of the magnetic field detecting layer. A magnetization amount per unit area of the magnetic field detecting layer is less than 0.2 [memu/cm].

A TMR element and a corrective AMR element are series-connected between a power supply and a ground. The resistance value of the corrective AMR element is set so as to offset an output error in the rotation angle of an external magnetic field, which is included in the resistance value of the TMR element. The resistance value of the corrective AMR element is smaller than that of the TMR element. An increased voltage can be applied from the power supply to the TMR element. It is possible to increase, in the resistance value of the TMR element, the amount of change that depends on the rotation angle of the external magnetic field. This makes it possible to increase, in the output of a magnetic sensor, the amount of change that depends on the rotation angle of the external magnetic field. The sensitivity of the magnetic sensor can be increased.

A magnetic sensor is provided, including: a substrate; a plurality of magneto resistance element portions, disposed above the substrate, each including: a free magnetic layer having a magnetization direction changeable by an external magnetic field; and a pin magnetic layer having a fixed magnetization direction; and a plurality of heater portions corresponding to the magneto resistance element portions, respectively, and configured to heat a corresponding pin magnetic layer, wherein the magnetization direction of the pin magnetic layer of one magneto resistance element portion is different from the magnetization direction of the pin magnetic layer of another magneto resistance element portion on a plane parallel to a surface of the substrate, when the external magnetic field is applied to each of the magneto resistance element portions, the magnetic sensor detects a physical amount based on a change in a resistance of each of the magneto resistance element portions.

Growing community of inventors

Nagoya, Japan

Takamoto Furuichi