Magnetization rotational element, magnetoresistance effect element, and memory device
A magnetization rotational element includes a ferromagnetic metal layer, and a spin-orbit torque wiring extending in a first direction intersecting a lamination direction of the ferromagnetic metal layer and having the ferromagnetic metal layer positioned on one surface thereof, in which a direction of spin injected from the spin-orbit torque wiring into the ferromagnetic metal layer intersects a magnetization direction of the ferromagnetic metal layer, and a damping constant of the ferromagnetic metal layer is larger than 0.01.
1. A magnetization rotational element comprising:
a ferromagnetic metal layer;
a spin-orbit torque wiring extending in a first direction intersecting a lamination direction of the ferromagnetic metal layer, the ferromagnetic metal layer being positioned on one surface of the spin-orbit torque wiring; and
an insertion layer provided between the ferromagnetic metal layer and the spin-orbit torque wiring, wherein:
the insertion layer includes a heavy metal having a melting point of 2000° C. or higher or an alloy containing the heavy metal,
a film thickness of the insertion layer is less than a film thickness of one atomic layer thereof, and
the insertion layer includes a plurality of gaps.
2. The magnetization rotational element according to claim 1 , wherein a film thickness of the ferromagnetic metal layer is 4 nm or less.
3. A magnetoresistance effect element comprising:
the magnetization rotational element according to claim 1 ; and
a nonmagnetic layer and a second ferromagnetic metal layer laminated in this order on a surface of the ferromagnetic metal layer on a side opposite to the spin-orbit torque wiring.
4. A memory device comprising the magnetoresistance effect element according to claim 3 .
5. The magnetization rotational element according to claim 1 , wherein the heavy metal is selected from the group consisting of Ta, Ir, and W.
6. The magnetization rotational element according to claim 1 , wherein a direction of spin injected from the spin-orbit torque wiring into the ferromagnetic metal layer intersects a magnetization direction of the ferromagnetic metal layer.
7. The magnetization rotational element according to claim 6 , wherein the direction of the spin injected from the spin-orbit torque wiring into the ferromagnetic metal layer is inclined by 45° or more and 90° or less with respect to the magnetization direction of the ferromagnetic metal layer.
8. The magnetization rotational element according to claim 7 , wherein a film thickness of the ferromagnetic metal layer is 4 nm or less.
9. The magnetization rotational element according to claim 1 , wherein the film thickness of the insertion layer is an average film thickness.
10. The magnetization rotational element according to claim 1 , wherein the insertion layer is configured to transmit the spin from the spin-orbit torque wiring to the ferromagnetic metal layer via the plurality of gaps.