Tdk Corporation

Alps Electric Co., Ltd.

Kazumasa Nishimura

Masamichi Saito

Naoya Hasegawa

Yosuke Ide

Ryo Nakabayashi

Yoshihiro Nishiyama

Masahiko Ishizone

Hidekazu Kobayashi

Akio Hanada

Kenichi Tanaka

Eiji Umetsu

Kazuaki Ikarashi

Takuya Seino

Kota Asatsuma

Hasahiko Ishizone

Yoshihiro Nishiyana

Hidekezu Kobayashi

Norimasa Okanishi

Naoya Hasegawn

A tunneling magnetic sensing element includes a laminate in which a pinned magnetic layer having a magnetization direction pinned, an insulating barrier layer, and a free magnetic layer having a magnetization direction variable with an external magnetic field are laminated in order from below. The insulating barrier layer is made of Mg&#x2014;O. The free magnetic layer has a soft magnetic layer and an enhanced layer disposed between the soft magnetic layer and the insulating barrier layer to have a spin polarization ratio higher than the soft magnetic layer. An insertion magnetic layer made of one selected from Co&#x2014;Fe&#x2014;B, Co&#x2014;B, Fe&#x2014;B, and Co&#x2014;Fe is inserted into the soft magnetic layer in a direction parallel to the interface of each layer constituting the laminate, and the soft magnetic layer is divided into multiple layers in a thickness direction through the insertion magnetic layer.

Tunneling magnetic sensing element with insertion magnetic layer inspired into soft magnetic layer

A tunneling magnetic sensing element includes: a pinned magnetic layer whose direction of magnetization is pinned in one direction; an insulating barrier layer; and a free magnetic layer whose direction of magnetization changes in response to an external magnetic field. The pinned magnetic layer, the insulating barrier layer and the free magnetic layer are deposited in the named order. A first protective layer composed of a platinum-group element is disposed on the free magnetic layer, and a second protective layer composed of Ti is disposed on the first protective layer.

Tunneling magnetic sensing element and method for manufacturing the same

A tunneling magnetic sensing element includes a laminate in which an underlayer, a seed layer, an antiferromagnetic layer, a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer are laminated in order from below. The insulating barrier layer is made of Mg&#x2014;O. The underlayer is made of Ti, and the seed layer is made of one selected from a group consisting of Ni&#x2014;Fe&#x2014;Cr and Ru.

Tunneling magnetic sensing element including MGO film as insulating barrier layer

A tunnel magnetoresistive element includes a laminate including a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer. The insulating barrier layer is composed of Ti&#x2014;Mg&#x2014;O or Ti&#x2014;O. The free magnetic layer includes an enhancement sublayer, a first soft magnetic sublayer, a nonmagnetic metal sublayer, and a second soft magnetic sublayer. For example, the enhancement sublayer is composed of Co&#x2014;Fe, the first soft magnetic sublayer and the second soft magnetic sublayer are composed of Ni&#x2014;Fe, and the nonmagnetic metal sublayer is composed of Ta. The total thickness of the average thickness of the enhancement sublayer and the average thickness of the first soft magnetic sublayer is in the range of 25 to 80 angstroms. Accordingly, the tunneling magnetoresistive element can consistently have a higher rate of resistance change than before.

Tunneling magnetoresistive element including multilayer free magnetic layer having inserted nonmagnetic metal sublayer

A free magnetic layer has a laminated structure in which a first magnetic sublayer composed of Co&#x2014;Fe or Fe and a second magnetic sublayer composed of Co&#x2014;Fe&#x2014;B or Fe&#x2014;B are formed, in that order, on an insulating barrier layer composed of Mg&#x2014;O. This effectively improves the rate of change in resistance (&#x394;R/R) compared with the related art.

Tunneling magnetic sensing element and method for producing same

A tunneling magnetic sensing element includes a pinned magnetic layer whose magnetization direction is pinned in one direction, an insulating barrier layer disposed on the pinned magnetic layer, a free magnetic layer whose magnetization direction varies in response to an external magnetic field disposed on the insulating barrier layer, and a first protective layer composed of iridium-manganese (IrMn) disposed on the free magnetic layer. Consequently, a high rate of change in resistance is obtained and the magnetostriction of the free magnetic layer is low, compared with a tunneling magnetic sensing element which is not provided with a first protective layer.

Tunneling magnetic sensing element including free magnetic layer and IrMn protective layer disposed thereon and method for manufacturing the same

An underlying layer is composed of Co&#x2014;Fe&#x2014;B that is an amorphous magnetic material. Thus, the upper surface of the underlying layer can be taken as a lower shield layer-side reference position for obtaining a gap length (GL) between upper and lower shields, resulting in a narrower gap than before. In addition, since the underlying layer has an amorphous structure, the underlying layer does not adversely affect the crystalline orientation of individual layers to be formed thereon, and the surface of the underlying layer has good planarizability. Accordingly, PW50 (half-amplitude pulse width) and SN ratio can be improved more than before without causing a decrease in rate of change in resistance (&#x394; R/R) or the like, thereby achieving a structure suitable for increasing recording density.

Magnetic sensing element and method for manufacturing the same

A tunnel magnetoresistive sensor includes a pinned magnetic layer, an insulating barrier layer formed of Mg&#x2014;O, and a free magnetic layer. A barrier-layer-side magnetic sublayer constituting at least part of the pinned magnetic layer and being in contact with the insulating barrier layer includes a first magnetic region formed of CoFeB or FeB and a second magnetic region formed of CoFe or Fe. The second magnetic region is disposed between the first magnetic region and the insulating barrier layer.

Tunnel magnetoresistive sensor in which at least part of pinned layer is composed of CoFeB layer and method for manufacturing the tunnel magnetoresistive sensor

In a tunneling magnetoresistive element, an insulating barrier layer is made of Mg&#x2014;O, and a first pinned magnetic layer has a laminated structure in which a nonmagnetic metal sublayer made of Ta is interposed between a lower ferromagnetic sublayer and an upper ferromagnetic sublayer. The nonmagnetic metal sublayer has an average thickness of about 1 &#x212b; or more and about 5 &#x212b; or less.

Tunneling magnetoresistive element which includes Mg-O barrier layer and in which nonmagnetic metal sublayer is disposed in one of magnetic layers

A tunneling magnetic detecting element includes an insulating barrier layer having a layered structure including a Ti&#x2014;O sublayer and a Ta&#x2014;O sublayer. The Ta concentration in the insulating barrier layer is set to be more than 0 at % but not more than about 7 at % with respect to a total of 100 at % of Ti and Ta constituting the insulating barrier layer.

Tunneling magnetic detecting element having insulation barrier layer and method for making the same

A tunneling magnetic sensor includes a pinned magnetic layer of which the magnetization is pinned in one direction, an insulating barrier layer, and a free magnetic layer of which the magnetization is varied by an external magnetic field, these layers being arranged in that order from the bottom. A first protective layer made of magnesium (Mg) is disposed on the free magnetic layer. The tunneling magnetic sensor has a larger change in reluctance as compared to conventional magnetic sensors including no first protective layers or including first protective layers made of Al, Ti, Cu, or an Ir&#x2014;Mn alloy. The free magnetic layer has lower magnetostriction as compared to free magnetic layers included in the conventional magnetic sensors.

Tunneling magnetic sensor including free magnetic layer and magnesium protective layer disposed thereon

A tunneling magnetic sensor includes a platinum layer between a pinned magnetic layer and an insulating barrier layer. The platinum layer can probably vary the barrier height (potential height) and barrier width (potential width) of the insulating barrier layer to reduce the absolute value of VCR, thus providing higher operating stability than known tunneling magnetic sensors. In addition, the insulating barrier layer can achieve increased flatness at its bottom interface (where the insulating barrier layer starts to be formed). The tunneling magnetic sensor can therefore provide a higher rate of resistance change (&#x394;R/R) at low RA than known tunneling magnetic sensors.

Tunneling magnetic sensor including platinum layer and method for producing the same

A tunneling magnetic sensing element including an Mg&#x2014;O insulating barrier which can maintain favorable soft-magnetic properties of a free magnetic layer and can have a high resistance change ratio (&#x394;R/R) compared to known tunnel magnetic sensing elements is disclosed, and a method of manufacturing such a tunneling magnetic sensing element is also disclosed. An enhance layer (second magnetic layer) composed of CoFehaving a Fe composition ratio X of about 30 to 100 at % is disposed on the Mg&#x2014;O insulating barrier. With this, the magnetostriction &#x3bb; of the free magnetic layer can be reduced and the resistance change ratio (&#x394;R/R) can be increased.

Tunneling magnetic sensing element having free layer containing CoFe alloy

A tunneling magnetic sensing element is provided, in which an increase in the magnetostriction of a free magnetic layer is reduced and the rate of change in resistance is high. A laminate Tconstituting the tunneling magnetic sensing element includes a portion in which a pinned magnetic layer, a barrier layer, and a free magnetic layer are disposed in that order from the bottom. An enhancing layer disposed on the barrier layer side of the free magnetic layer includes a first enhancing layer on the barrier layer side and a second enhancing layer on the soft magnetic layer side, and the Fe content of a CoFe alloy constituting the first enhancing layer is specified to be larger than the Fe content of the CoFe alloy of the second enhancing layer.

Tunneling magnetic sensing element including enhancing layer having high Fe concentration in the vicinity of barrier layer

A tunnel-type magnetic detecting element is provided. The tunnel-type magnetic detecting element includes a first ferromagnetic layer; an insulating barrier layer; and a second ferromagnetic layer. The first ferromagnetic layer, the second ferromagnetic layer, or both have a Heusler alloy layer contacting the insulating barrier layer. Equivalent planes represented by {110} surfaces, are preferentially oriented parallel to a film surface in the Heusler alloy layer. The insulating barrier layer is formed of MgO and the equivalent crystal planes represented by the {100} surfaces or the equivalent crystal planes represented by the {110} surfaces are oriented parallel to the film surface.

Growing community of inventors

Niigata-ken, Japan

Kazumasa Nishimura