National Institute for Materials Science

Takao Furubayashi

Kazuhiro Hono

Yukiko Takahashi

Seiji Mitani

Hiroaki Sukegawa

Koichiro Inomata

Ye Du

Tomoya Nakatani

Tadakatsu Ohkubo

Masaya Kodzuka

Zhenchao Wen

Jason Paul Hadorn

Jungwoo Koo

Masamitsu Hayashi

Taisuke Sasaki

Shinya Kasai

Wenhong Wang

Srinivasan Ananthakrishnan

Varaprasad Bollapragada

Rajanikanth Ammanabrolu

Jaivardhan Sinha

Shigeyuki Hirayama

Rong Shan

Sinha Jaivardhan

Provided is a precursor of a current-perpendicular-to-plane giant magnetoresistive element having a laminated structure of ferromagnetic metal layer/nonmagnetic metal layer/ferromagnetic metal layer, the precursor having a nonmagnetic intermediate layer containing a non-magnetic metal and an oxide in a predetermined ratio such that the distribution thereof is nearly uniform at the atomic level. Also provided is a current-perpendicular-to-plane giant magnetoresistive element having a current-confinement structure (CCP) which has: a current confinement structure region made of a conductive alloy and obtained by heat-treating a laminated structure of a ferromagnetic metal layer and a nonmagnetic intermediate layer at a predetermined temperature; and a high-resistance metal alloy region containing an oxide and surrounding the current confinement structure region.

Current-perpendicular-to-plane giant magnetoresistive element, precursor thereof, and manufacturing method thereof

Disclosed is a perpendicularly magnetized film structure using a highly heat resistant underlayer film on which a cubic or tetragonal perpendicularly magnetized film can grow, comprising a substrate of a cubic single crystal substrate having a (001) plane or a substrate having a cubic oriented film that grows to have the (001) plane; an underlayer formed on the substrate from a thin film of a metal having an hcp structure in which the [0001] direction of the thin metal film forms an angle in the range of 42&#xb0; to 54&#xb0; with respect to the &#x3c;001&#x3e; direction or the (001) orientation of the substrate; and a perpendicularly magnetized layer located on the metal underlayer and formed from a cubic material selected from a Co-based Heusler alloy and a cobalt-iron (CoFe) alloy having a bcc structure a constituent material, and grown to have the (001) plane.

Underlayer for perpendicularly magnetized film, perpendicularly magnetized film structure, perpendicular MTJ element, and perpendicular magnetic recording medium using the same

Disclosed is a perpendicularly magnetized film structure that uses a highly heat resistant underlayer film on which a cubic or tetragonal perpendicularly magnetized film can grow with high quality, the structure comprising any one substrate () of a cubic single crystal substrate having a (001) plane, or a substrate having a cubic oriented film that grows to have the (001) plane; an underlayer () formed on the substrate () from a thin film of a metal having an hcp structure, such as Ru or Re, in which the [0001] direction of the thin metal film forms an angle in the range of 42&#xb0; to 54&#xb0; with respect to the &#x3c;001&#x3e; direction or the (001) orientation of the substrate (); and a perpendicularly magnetized layer () located on the metal underlayer () and formed from a cubic material selected from the group consisting of a Co-based Heusler alloy, a cobalt-iron (CoFe) alloy having a bcc structure, and the like, as a constituent material, and grown to have the (001) plane.

The present invention addresses the problem of providing an element which uses the current-perpendicular-to-plane giant magnetoresistance (CPPGMR) effect of a thin film having the three-layer structure of ferromagnetic metal/non-magnetic metal/ferromagnetic metal. The problem is solved by a magnetoresistive element provided with a lower ferromagnetic layer and an upper ferromagnetic layer which contain a Heusler alloy, and a spacer layer sandwiched between the lower ferromagnetic layer and the upper ferromagnetic layer, the magnetoresistive element being characterized in that the spacer layer contains an alloy having a bcc structure. Furthermore, it is preferable for the alloy to have a disordered bcc structure.

Magnetoresistive element, magnetic head using magnetoresistive element, and magnetic reproducing device

The CPPGMR element of the present invention has an orientation layerformed on a substrateto texture a Heusler alloy into a (100) direction, an underlying layerthat is an electrode for magneto-resistance measurement stacked on the orientation layer, a lower ferromagnetic layerand an upper ferromagnetic layereach stacked on the underlying layerand made of a Heusler alloy, a spacer layersandwiched between the lower ferromagnetic layersand the upper ferromagnetic layers, and a cap layerstacked on the upper ferromagnetic layerfor surface-protection. This manner makes it possible to provide, inexpensively, an element using a current-perpendicular-to-plane giant magneto-resistance effect (CPPGMR) of a thin film having a trilayered structure of a ferromagnetic metal/a nonmagnetic metal/a ferromagnetic metal, thereby showing excellent performances.

Current-perpendicular-to-plane magneto-resistance effect element

Provided are an element structure in which a magnetic layer has a high magnetic anisotropy constant and saturated magnetization properties in a thickness of 1.5 nm or less, and a magnetic device that uses the element structure. A BCC metal nitride/CoFeB/MgO film structure that uses a nitride of a BCC metal as a seed layer is fabricated. The nitride amount in the BCC metal nitride is preferably less than 60% in terms of volume ratio based on 100% BCC metal. It is thereby possible to readily obtain a perpendicularly magnetized film having the magnetic properties that the perpendicular magnetic anisotropy is 0.1&#xd7;10erg/cmor more and the saturated magnetization is 200 emu/cmor more, even when the thickness of the magnetic layer is 0.3 nm or more and 1.5 nm or less.

Perpendicularly magnetized ultrathin film exhibiting high perpendicular magnetic anisotropy, method for manufacturing same, and application

To realize a spintronics device with high performance, it is an object of the present invention to provide a CoFe-based Heusler alloy having a spin polarization larger than 0.65, and a high performance spintronics devices using the same. A CoFe(GaGe) Heusler alloy shows a spin polarization higher than 0.65 by a PCAR method in a region of 0.25&#x3c;x&#x3c;0.60 and it has a Curie temperature as high as 1288K. A CPP-GMR device that uses the CoFe(GaGe) Heusler alloy as an electrode exhibits the world's highest MR ratio, an STO device exhibits high output, and an NLSV device exhibits a high spin signal.

[object Object]

Disclosed is a ferromagnetic tunnel junction structure which is characterized by having a tunnel barrier layer that comprises a non-magnetic material having a spinel structure. The ferromagnetic tunnel junction structure is also characterized in that the non-magnetic material is substantially MgAlO. The ferromagnetic tunnel junction is also characterized in that at least one of the ferromagnetic layers comprises a Co-based full Heusler alloy having an L2or B2 structure. The ferromagnetic tunnel junction structure is also characterized in that the Co-based full Heusler alloy comprises a substance represented by the following formula: CoFeAlSi(0&#x2266;x&#x2266;1). Also disclosed are a magnetoresistive element and a spintronics device, each of which utilizes the ferromagnetic tunnel junction structure and can achieve a high TMR value, that cannot be achieved by employing conventional tunnel barrier layers other than a MgO barrier.

Ferromagnetic tunnel junction structure, and magneto-resistive element and spintronics device each using same

Growing community of inventors

Ibaraki, Japan

Takao Furubayashi