Magnetization reversal device, memory element, and magnetic field generation device

Patent metadata

Field	Value
Publication number	US-9252356-B2
Application number	US-201013382801-A
Country	US
Kind code	B2
Filing date	Jul 9, 2010
Priority date	Jul 9, 2009
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A magnetization reversal device includes a ferromagnetic 12 body which is provided in an interconnection of a non-ferromagnetic dot 11 so that a part or a whole of the ferromagnetic dot is three-dimensionally buried in the interconnection of said non-ferromagnetic dot, and a spin injection source 13 which generates a spin-polarized pure spin current without a flow of charges, and which is provided in the interconnection of the non-ferromagnetic dot 11 to be in contact therewith so that the interconnection of the non-ferromagnetic dot serves as a common electrode, and the pure spin current flows into the ferromagnetic dot 2 through the interconnection of the non-magnetic body by the spin injection source 13 due to a diffusion current, to thereby reverse magnetization of the ferromagnetic dot 12 . By injecting the pure spin current, using this planar structure, it is possible to easily carry out the magnetization reversal of the ferromagnetic dot 12 even if it is a thick film ferromagnetic dot without being subjected to limitation of a spin diffusion length.

First claim

The invention claimed is:

1. A magnetization reversal device comprising:
a ferromagnetic dot provided in an interconnection of a non-ferromagnetic dot so that a whole upper surface of said ferromagnetic dot, and a part or a whole of a side surface thereof, a whole lower surface thereof and a part or a whole of the side surface thereof, or a whole surface thereof is three-dimensionally buried in the interconnection of said non-ferromagnetic dot;
multi-terminal spin injection means that generates a spin-polarized pure spin current without a flow of charges, and that is provided in the interconnection of said non-ferromagnetic dot to be in contact therewith so that the interconnection of said non-ferromagnetic dot serves as a common electrode; and
an electric current source that supplies said spin injection means and said non-ferromagnetic dot with electric currents;
characterized by the facts that:
one of said multi-terminal spin injection means is provided at a position except for a current path for a corresponding pure spin current between another spin injection means of said multi-terminal spin injection means and said ferromagnetic dot;
a closed circuit is at least formed by said multi-terminal spin injection means, said non-ferromagnetic dot and said electric current source, wherein a diffusion current is generated by energizing said closed circuit with the electric currents; and
said pure spin current flows into said ferromagnetic dot through the intermediary of the interconnection of said non-magnetic body due to said diffusion current by each of said multi-terminal spin injection means, to thereby reverse magnetization of said ferromagnetic dot.

2. A magnetization reversal device as set forth in claim 1 , characterized by the fact:
that a relationship between a first injection direction in which a corresponding pure spin current is injected by a first spin injection means and a second injection direction in which a corresponding pure spin current is injected by a second spin injection means is one except for either a parallel relationship or an antiparallel relationship; and
that a ratio of a quantity of the pure spin currents injected by said first spin injection means and said second spin injection means is adjusted in synchronization with a precession of the spins in said ferromagnetic dot so that a pure spin current featured by a vector having an optional direction in a two-dimensional plane is generated to a vector of the spins subjected to the precession in said ferromagnetic dot, whereby a torque acting on said spins is optimized.

3. A magnetization reversal device as set forth in claim 2 , characterized by the fact:
that the device further comprises a third injection means for injecting a pure spin current;
that a relationship between a third injection direction in which a corresponding pure spin current is injected by said third spin injection means, said first injection direction and/or said second injection direction is one except for either a parallel relationship or an antiparallel relationship; and
that a ratio of a quantity of the pure spin currents injected by said first spin injection means, said second spin injection means and said third spin injection means is adjusted in synchronization with a precession of the spins in said ferromagnetic dot so that a pure spin current featured by a vector having an optional direction is generated to a vector the spins subjected to the precession in said ferromagnetic dot, whereby a torque acting on said spins is optimized.

4. A magnetization reversal device as set forth in claim 1 , characterized by the fact:
that a relationship between a first injection direction in which a corresponding pure spin current is injected by a first spin injection means and a second injection direction in which a corresponding pure spin current is injected by a second spin injection means is one except for either a parallel relationship or an antiparallel relationship; and
that a ratio of a quantity of the pure spin currents injected by said first spin injection means and said second spin injection means is adjusted in synchronization with a precession of the spins in said ferromagnetic dot so that a pure spin current featured by a vector having an optional direction in a two-dimensional plane is generated to a vector of the spins subjected to the precession in said ferromagnetic dot, whereby a torque acting on said spins is optimized.

5. A magnetization reversal device as set forth in claim 4 , characterized by the fact:
that the device further comprises a third injection means for injecting a pure spin current;
that a relationship between a third injection direction in which a corresponding pure spin current is injected by said third spin injection means, said first injection direction and/or said second injection direction is one except for either a parallel relationship or an antiparallel relationship; and
that a ratio of a quantity of the pure spin currents injected by said first spin injection means, said second spin injection means and said third spin injection means is adjusted in synchronization with a precession of the spins in said ferromagnetic dot so that a pure spin current featured by a vector having an optional direction is generated to a vector the spins subjected to the precession in said ferromagnetic dot, whereby a torque acting on said spins is optimized.

6. A memory element using a magnetization reversal device as set forth in claim 1 , characterized by the fact:
that the ferromagnetic dot is three-dimensionally provided at a position of any one point of intersection of a conductor non-ferromagnetic dot where horizontal lines and vertical lines are perpendicularly intersected with each other, in a state that a whole upper surface of said ferromagnetic dot, and a part or a whole of a side surface thereof, a whole lower surface thereof and a part or a whole of the side surface thereof, or a whole surface thereof is in contact with the interconnection of said non-ferromagnetic dot;
the spin injection means is provided at positions of any other ones of said points of intersection which are adjacent to said any one point of intersection at which said ferromagnetic dot is provided so that the spin injection means is in contact with the interconnection of said non-ferromagnetic dot so that the interconnection of said non-ferromagnetic dot serves as a common electrode; and
magnetization of said ferromagnetic dot is reversed by the pure spin current from the spin injection means so that a bit is written therein.

7. A memory element as set forth in claim 6 , characterized by the fact that the interconnection of said non-magnetic body of said conductor body has not only the vertically and horizontally intersected portion but also a perpendicularly and diagonally intersected portion.

8. A memory element as set forth in claim 6 , characterized by the fact:
that at least a first spin injection means and a second spin injection means are provided at other points of intersection in the interconnection of said non-magnetic body, a relationship between a first injection direction in which a pure spin current is injected by said first spin injection means and a second injection direction in which a pure spin current is injected by said second spin injection means being one except for either a parallel relationship or an antiparallel relationship; and
that a ratio of a quantity of the pure spin currents injected by said first spin injection means and said second spin injection means is adjusted in synchronization with a precession of the spins in said ferromagnetic dot so that a pure spin current having an optional direction in a two-dimensional plane is generated to the spins subjected to the prece

Assignees

• Kimura Takashi
• Hamaya Kohei
• Univ Kyushu Nat Univ Corp

Inventors

• Kimura Takashi
• Hamaya Kohei

Classifications

• H01L43/08 Primary

  Electricity · mapped topic

• G11C11/16

  using elements in which the storage effect is based on magnetic spin effect · CPC title

• H01L27/22

  Electricity · mapped topic

• H10N59/00

  Integrated devices, or assemblies of multiple devices, comprising at least one galvanomagnetic or Hall-effect element covered by groups H10N50/00 - H10N52/00 (MRAM devices H10B61/00) · CPC title

• G11C11/1659

  Cell access · CPC title