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US 7,489,541 B2Granted
Spin-transfer switching magnetic elements using ferrimagnets and magnetic memories using the magnetic elements
AssigneeGrandis, Inc.
InventorsMahendra Pakala, Eugene Youjun Chen, Yiming Huai
Life of this patent
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Abstract
A method and system for providing a magnetic element are disclosed. The method and system include providing a pinned layer, providing a spacer layer, and providing a free layer. The free layer is ferrimagnetic and includes at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnetic, and a bilayer. The bilayer includes a rare earth-transition metal alloy layer and a spin current enhancement layer. The magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element.
Claims33
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the pinned layer is a synthetic pinned layer including a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic conductive layer residing between the first ferromagnetic layer and the second ferromagnetic layer.
2 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the spacer layer is an insulating barrier layer and wherein the insulating barrier layer includes crystalline MgO.
2 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the free layer has a saturation magnetization of not more than six hundred emu per cubic centimeter.
2 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- an additional spacer layer;
- and
- an additional pinned layer, the additional spacer layer residing between the free layer and the pinned layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- and
- wherein the free layer includes the rare-earth transition metal alloy layer and wherein the free layer further includes
- an additional spin current enhancement layer residing between the rare earth-transition metal alloy layer and the additional spacer layer.
7 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- an additional spacer layer;
- and
- an additional pinned layer, the additional spacer layer residing between the free layer and the pinned layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- and
- wherein the additional pinned layer is a synthetic pinned layer including a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic conductive spacer layer residing between the first ferromagnetic layer and the second ferromagnetic layer.
6 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- an additional spacer layer;
- an additional pinned layer, the additional spacer layer residing between the free layer and the pinned layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- and
- wherein the at least one of the spacer layer and the additional spacer layer is an insulating barrier layer including at least one of crystalline MgO and alumina.
5 more elements
A magnetic element comprising:
- a pinned layer;
- a spacer layer;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer;
- an additional spacer layer;
- and
- an additional pinned layer, the additional spacer layer residing between the free layer and the pinned layer;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element
- wherein the free layer includes the rare earth-transition metal alloy layer and the spin current enhancement layer;
- and wherein the free layer further includes:
- an insertion layer between the rare earth-transition metal alloy layer and the spin current enhancement layer, the insertion layer including at least one of Ru, Rh, Ta, and Cr and having a thickness of not more than one nanometer.
7 more elements
A magnetic element comprising:
- a pinned layer;
- a barrier layer including at least one of alumina and crystalline MgO;
- a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare earth-transition metal alloy, a half-metallic ferrimagnetic, and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, the rare earth-transition metal alloy layer including at least one of CoREx and (CoREj)Zk, where RE includes at least one of Gd, Tb, Dy, Ho, Em, and Tm and x is at least six and not more than thirty percent or (CoREj)Zk, Z includes at least one of Au, Cu, B, Cr, and Mo, k is at least five and not more than forty percent, and j is at least ten and not more than thirty percent, the spin current enhancement layer including an alloy including at least one of Co, Ni, and Fe, the ferrimagnetic alloy including at least one of Mn2Sb, Mn2Sn, Mn3Ga, Mn3Ge2, Mn3In, FeGe2, FeSe, Cr3As2, and CrPt3, the heavy rare-earth-transition metal alloy including RCo5 where R includes at least one of Gd, Tb, Dy, Ho, Eb, and Tm, the garnet includes Yttrium Iron Garnet, the conductive ferrite includes Fe3O4, the half-metallic ferrimagnet including at least one of Co2(Cr1-xFex)Al, Co2MnAl, or Co2MnSi, the free layer having a saturation magnetization of not more than six hundred emu per cubic centimeter;
- wherein the magnetic element is configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element.
1 more element
A magnetic memory comprising:
- a plurality of magnetic elements, each of the plurality of magnetic elements including a pinned layer, a spacer layer, and a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, each of the plurality of the magnetic elements being configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the spacer layer includes at least one of a barrier layer, a conductor and a nano-oxide layer;
- and
- wherein the free layer further has lateral dimensions not more than two hundred nanometers.
1 more element
A magnetic memory comprising:
- a plurality of magnetic elements, each of the plurality of magnetic elements including a pinned layer, a spacer layer, and a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, each of the plurality of the magnetic elements being configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the spacer layer includes at least one of a barrier layer, a conductor and a nano-oxide layer;
- and
- wherein the free layer includes the bilayer including the rare earth transition metal alloy layer and the spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer.
1 more element
A magnetic memory comprising:
- a plurality of magnetic elements, each of the plurality of magnetic elements including a pinned layer, a barrier layer including at least one of alumina and crystalline MgO, and a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnet and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, the rare earth-transition metal alloy layer including at least one of CoREx and (CoREj)Zk, where RE includes at least one of Gd, Tb, Dy, Ho, Em, and Tm and x is at least six and not more than thirty percent, k is at least five and not more than forty percent, and j is at least ten and not more than thirty percent, the ferrimagnetic alloy including at least one of Mn2Sb, Mn2Sn, Mn3Ga, Mn3Ge2, Mn3In, FeGe2, FeSe, Cr3As2, and CrPt3, the heavy rare-earth-transition metal alloy including RCo5 where R includes at least one of Gd, Tb, Dy, Ho, Eb, and Tm, the garnet includes Yttrium Iron Garnet, the conductive ferrite includes Fe3O4, the half metallic ferrimagnet includes at least one of Co2(Cr1-xFex,)Al, Co2MnAl, and Co2MnSi, each of the plurality of the magnetic elements being configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the free layer further has lateral dimensions not more than two hundred nanometers.
A magnetic memory comprising:
- a plurality of magnetic elements, each of the plurality of magnetic elements including a pinned layer, a barrier layer including at least one of alumina and crystalline MgO, and a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnet and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, the rare earth-transition metal alloy layer including at least one of CoREx and (CoREj)Zk, where RE includes at least one of Gd, Tb, Dy, Ho, Em, and Tm and x is at least six and not more than thirty percent, k is at least five and not more than forty percent, and j is at least ten and not more than thirty percent, the ferrimagnetic alloy including at least one of Mn2Sb, Mn2Sn, Mn3Ga, Mn3Ge2, Mn3In, FeGe2, FeSe, Cr3As2, and CrPt3, the heavy rare-earth-transition metal alloy including RCo5 where R includes at least one of Gd, Tb, Dy, Ho, Eb, and Tm, the garnet includes Yttrium Iron Garnet the conductive ferrite includes Fe3O4, the half metallic ferrimagnet includes at least one of Co2(Cr1-xFex,)Al, Co2MnAl, and Co2MnSi, each of the plurality of the magnetic elements being configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- and
- wherein the free layer includes the bilayer including the rare earth transition metal alloy layer and the spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer.
A magnetic memory comprising:
- a plurality of magnetic elements, each of the plurality of magnetic elements including a pinned layer, a spacer layer, and a free layer, the free layer being ferrimagnetic and including at least one of a conductive ferrite, a garnet, a ferrimagnetic alloy excluding a rare earth, a heavy rare-earth-transition metal alloy, a half-metallic ferrimagnet, and a bilayer including a rare earth-transition metal alloy layer and a spin current enhancement layer residing between the rare-earth transition metal alloy layer and the spacer layer, each of the plurality of the magnetic elements being configured to allow the free layer to be switched using spin transfer when a write current is passed through the magnetic element;
- wherein the spacer layer includes at least one of a barrier layer, a conductor and a nano-oxide layer;
- and
- wherein the rare-earth transition metal alloy layer includes at least one of CoREw and (CoREx)Zy, where RE includes at least one of Gd, Tb, Dy, Ho, Em, and Tm, Z includes at least one of Au, Cu, B, Cr, and Mo, w is at least six and not more than thirty percent, x is at least ten and not more than thirty percent, and y is at least five and not more than forty percent, and wherein the half metallic ferrimagnet includes at least one of Co2(Cr1-xFex)Al, Co2MnAl, and Co2MnSi.
1 more element
Dependencies are inferred from the claim text.