Three terminal magnetic element
View Patent ↗Techniques and magnetic devices associated with a magnetic element are described that includes a presetting fixed layer having a presetting fixed layer magnetization, a free layer having a changeable free layer magnetization, and a fixed layer having a fixed layer magnetization, where a presetting current pulse applied between the presetting fixed layer and free layer operates to preset the free layer magnetization in advance of a write pulse. Techniques and magnetic devices associated with a magnetic element are described that includes a first terminal, a first magnetic tunnel junction, a second terminal, a second magnetic tunnel junction, and a third terminal, where a current pulse applied between the first and second terminal operate to switch the state of the first magnetic tunnel junction and a current applied between the second and third terminal operate to switch the state of the second magnetic tunnel junction.
1. A magnetic memory device comprising
a magnetic element including:
a presetting fixed layer having a fixed layer magnetization fixed in a direction substantially perpendicular to a plane of the presetting fixed layer;
a fixed layer having a fixed layer magnetization fixed in a direction substantially in a plane of the fixed layer;
a free layer between the presetting fixed layer and fixed layer having a free layer magnetization with in-plane anisotropy;
a first nonmagnetic spacer layer between the presetting fixed layer and the free layer; and
a second nonmagnetic spacer layer between the free layer and the fixed layer; and
circuitry configured to apply a presetting current pulse and a write current pulse during a write operation,
wherein:
the presetting current pulse includes a current between the presetting fixed layer and free layer that presets the magnetization of the free layer magnetization at some angle away from an easy axis direction utilizing a spin transfer torque,
the write current pulse includes a current between the free layer and fixed layer that reverses direction of magnetization of the free layer utilizing a spin transfer torque, and
the circuitry is configured to apply the write current pulse sequentially after a beginning of the presetting current pulse and before the magnetization of the free layer relaxes back to be substantially parallel with the anisotropy of the free layer.
2. The magnetic memory device of claim 1 wherein the second nonmagnetic spacer layer is an insulator.
3. The magnetic memory device of claim 1 further comprising:
a first electrical contact to the presetting fixed layer;
a second electrical contact to the free layer;
a third electrical contact to the fixed layer;
wherein the circuitry is configured to provide the presetting pulse between the first electrical contact and second electrical contact and is configured to provide the write pulse between the second electrical contact and third electrical contact.
4. The magnetic memory device of claim 3 wherein the lateral dimensions of the presetting fixed layer, the free layer, and the fixed layer are different.
5. A magnetic memory device comprising
a magnetic element including:
a presetting fixed layer having a fixed layer magnetization fixed in a direction substantially perpendicular to a plane of presetting fixed layer;
a fixed layer having a fixed layer magnetization fixed in a direction substantially in a plane of the fixed layer;
a free layer having a free layer magnetization with in-plane anisotropy;
a nonmagnetic spacer layer between the presetting fixed layer and the free layer and between the fixed layer and the free layer wherein the fixed layer and presetting fixed layer are laterally separated;
and circuitry configured to apply a presetting current pulse and a write current pulse during a write operation, wherein:
the presetting current pulse includes a current between the presetting fixed layer and free layer that presets the magnetization of the free layer magnetization at some angle away from an easy axis direction utilizing a spin transfer torque,
the write current pulse includes a current between the free layer and fixed layer that reverses a direction of the magnetization of the free layer utilizing a spin transfer torque, and
the circuitry is configured to apply the write current pulse sequentially after a beginning of the presetting current pulse and before the magnetization of the free layer relaxes back to be substantially parallel with the anisotropy of the free layer.
6. The magnetic memory device of claim 5 wherein the nonmagnetic spacer layer is an insulator.
7. The magnetic memory device of claim 5 further comprising:
a first electrical contact to the presetting fixed layer;
a second electrical contact to the free layer;
a third electrical contact to the fixed layer;
wherein the circuitry is configured to provide the presetting pulse between the first electrical contact and second electrical contact and is configured to provide the write pulse between the second electrical contact and third electrical contact.
8. A magnetic memory device comprising
a magnetic element including:
a presetting fixed layer having a fixed layer magnetization fixed in a direction substantially in a plane of the presetting fixed layer;
a fixed layer having a fixed layer magnetization fixed substantially in a direction perpendicular to a plane of the fixed layer;
a free layer between the presetting fixed layer and fixed layer having a free layer magnetization with an out of plane anisotropy, which overcomes demagnetizing energy;
a first nonmagnetic spacer layer between the presetting fixed layer and the free layer;
a second nonmagnetic spacer layer between the free layer and the fixed layer; and
circuitry configured to apply a presetting current pulse and a write current pulse during a write operation, wherein:
the presetting current pulse includes a current between the presetting fixed layer and free layer that presets the magnetization of the free layer magnetization partially in-plane utilizing a spin transfer torque,
the write current pulse includes a current between the free layer and fixed layer that reverses the direction of the magnetization of the free layer utilizing a spin transfer torque, and
the circuitry is configured to apply the write current pulse sequentially after a beginning of the presetting current pulse and before the magnetization of the free layer relaxes back to be substantially parallel with the anisotropy easy axis of the free layer.
9. The magnetic memory device of claim 8 wherein the second nonmagnetic spacer layer is an insulator.
10. The magnetic memory device of claim 8 further comprising:
a first electrical contact to the presetting fixed layer;
a second electrical contact to the free layer;
a third electrical contact to the fixed layer;
wherein the circuitry is configured to provide the presetting pulse between the first electrical contact and second electrical contact and is configured to provide the write pulse between the second electrical contact and third electrical contact.
11. The magnetic memory device of claim 10 wherein the lateral dimensions of the presetting fixed layer, the free layer, and the fixed layer are different.
12. A magnetic memory device comprising
a magnetic element including:
a presetting fixed layer having a fixed layer magnetization fixed substantially in a direction in a plane of presetting fixed layer;
a fixed layer having a fixed layer magnetization fixed substantially in a direction perpendicular to a plane of the fixed layer;
a free layer having a free layer magnetization with an out of plane anisotropy, which overcomes demagnetizing energy;
a nonmagnetic spacer layer between the presetting fixed layer and the free layer and between the fixed layer and the free layer wherein the fixed layer and presetting fixed layer are laterally separated;
and circuitry configured to apply a presetting current pulse and a write current pulse during a write operation, wherein:
the presetting current pulse includes a current between the presetting fixed layer and free layer to preset the magnetization of the free layer magnetization partially in-plane utilizing a spin transfer torque,
the write current pulse includes a current between the free layer and fixed layer that reverses the direction of the magnetization of the free layer utilizing a spin transfer torque, and
the circuitry is configured to apply the write current pulse sequentially after a beginning of the presetting current pulse and before the magnetization of the free layer relaxes back to be substantially parallel with the anisotropy easy axis of the free layer.
13. The magnetic memory device of claim 12 wherein the nonmagnetic spacer layer is an insulator.
14. The magnetic memory device of claim 12 further comprising:
a first electrical contact to the presetting fixed layer;
a second electrical contact to the free layer;
a third electrical contact to the fixed layer;
wherein the circuitry is configured to provide the presetting pulse between the first electrical contact and second electrical contact and is configured to provide the write pulse between the second electrical contact and third electrical contact.