Nec Corporation

Tsutomu Mitsuzuka

Atsushi Kamijo

Hisanao Tsuge

Ken-ichi Shimura

A magnetic sensor have a magnetic field sensing portion having an alloy metal thin film including Ni, Fe and Co as main components and having a magneto-resistance effect, and detects two or more magnetic fields, at least one of which magnetic fields to be detected is 2.5 mT or more, and among which magnetic fields to be detected the minimum magnetic field and the maximum magnetic field are separated by 0.5 mT or more. The alloy metal thin film has an absolute value of magneto-striction constant of 1.5&#xd7;10or less, an anisotropic magnetic field of 8 Oe or more as well as 16 Oe or less, and a magnetic resistance change ratio of 2.5% or more. The alloy metal thin film is within a composition range which concurrently fulfills the following relations: 21x+19y&#x2266;1869, 5x+28y&#x2267;546, y&#x2266;11, and x+y&#x2267;85, where the composition ratio of Ni is represented by x % by weight, while the composition ratio of Co is represented by y % by weight.

Magnetic sensor, method of manufacturing the same, and electronic device

In accordance with a method of producing an MR (MagnetoResistive) device including a ferromagnetic tunnel junction made up of a first ferromagnetic layer, an insulation layer formed on the first ferromagnetic layer and a second ferromagnetic layer formed on the insulation layer, a metal or a semiconductor is deposited on the first ferromagnetic layer. The metal or the semiconductor is then caused to react to oxygen of a ground level to become an oxide layer, which is the oxide of the metal or that of the semiconductor. Subsequently, the oxide layer is caused to react to oxygen of an excitation level to form the insulation layer. The second ferromagnetic layer is formed on the insulation layer.

Growing community of inventors

Yamanashi, Japan

Tsutomu Mitsuzuka