Magnetoresistance effect element and magnetic memory
Provided is an X-type 3-terminal STT-MRAM (spin orbital torque magnetization reversal component) having a high thermal stability index Δ and a low writing current I C in a balanced manner. A magnetoresistance effect element has a configuration of channel layer ( 1 )/barrier layer non adjacent magnetic layer ( 2 b )/barrier layer adjacent magnetic layer ( 2 a )/barrier layer ( 3 ).
1. A magnetoresistance effect element, comprising:
a channel layer,
a recording layer disposed adjacent to said channel layer, and including a ferromagnetic substance, and
a barrier layer disposed adjacent to said recording layer on an opposite side thereof to said channel layer, and constituted by an insulator,
wherein said recording layer has at least two or more magnetic layers including films having different magnetic characteristics,
wherein said two or more magnetic layers consist of one barrier-layer-adjacent-magnetic-layer disposed adjacent to said barrier layer, and one or more barrier-layer-non-adjacent-magnetic-layers that are not adjacent to said barrier layer,
wherein the barrier-layer-adjacent-magnetic-layer and the barrier-layer-non-adjacent-magnetic-layers are magnetically bonded, and a magnetization direction of both of said barrier-layer-adjacent-magnetic-layer and said barrier-layer-non-adjacent-magnetic-layers is in parallel with a film surface, is variable, and is made reversal in a same direction,
wherein a current in a direction substantially in parallel with said recording layer is introduced to said channel layer, thereby making a magnetization direction of said recording layer reversal,
wherein said barrier-layer-non-adjacent-magnetic-layer is constituted by a magnetic material film made of a Co film serving as an in-plane axis of easy magnetization, and
wherein an axis of easy magnetization of said recording layer is in a direction at within ±45° with respect to a direction of said current.
2. The magnetoresistance effect element according to claim 1 , wherein said barrier-layer-adjacent-magnetic-layer includes at least Fe, and said barrier layer includes at least O.
3. The magnetoresistance effect element according to claim 1 , wherein a non-magnetic insertion layer is inserted between said two or more magnetic layers forming said recording layer.
4. The magnetoresistance effect element according to claim 1 , wherein said channel layer has a heavy metal.
5. The magnetoresistance effect element according to claim 1 , wherein a longitudinal effective field to be applied to said recording layer from a direction perpendicular to a film surface of said channel layer due to introduction of a current to said channel layer makes the magnetization direction of said recording layer reversal.
6. The magnetoresistance effect element according to claim 1 , wherein said channel layer has a shape extended in the direction of said current to be introduced, and
said recording layer has substantially a two-fold symmetric shape in a recording layer plane, and a longitudinal direction has a component in the direction of said current.
7. The magnetoresistance effect element according to claim 1 , wherein a pulse width of the current to be introduced to said channel layer is 0.3 to 10 nanoseconds.
8. A magnetic memory comprising the magnetoresistance effect element according to claim 1 .
9. A magnetoresistance effect element, comprising:
a channel layer,
a recording layer disposed adjacent to said channel layer, and including a ferromagnetic, and
a barrier layer disposed adjacent to said recording layer on an opposite side thereof to said channel layer, and including an insulator,
wherein said recording layer has at least two or more magnetic layers including films having different magnetic characteristics,
wherein said two or more magnetic layers consists of one barrier-layer-adjacent-magnetic-layer disposed adjacent to said barrier layer, and one or more barrier-layer-non-adjacent-magnetic-layers not adjacent to said barrier layer,
wherein the barrier-layer-adjacent-magnetic-layer and the barrier-layer-non-adjacent-magnetic-layers are magnetically bonded, and a magnetization direction of both of said barrier-layer-adjacent-magnetic-layer and said barrier-layer-non-adjacent-magnetic-layers is in parallel with a film surface, is variable, and is made reversal in a same direction,
wherein a current in a direction substantially in parallel with said recording layer is introduced to said channel layer, thereby making a magnetization direction of said recording layer reversal,
wherein said at least one or more barrier-layer-non-adjacent-magnetic-layers is constituted by a magnetic material film made of a Co film serving as an in-plane axis of easy magnetization, and
wherein an axis of easy magnetization of said recording layer is in a direction at within ±45° with respect to a direction of said current.