Three-dimensional arrays with magnetic tunnel junction devices including an annular discontinued free magnetic layer and a planar reference magnetic layer

1. A device comprising:

a plurality of annular structures, each annular structure including an annular non-magnetic layer disposed about an annular conductive layer, a first annular free magnetic layer and a second annular free magnetic. layer disposed about the annular non-magnetic layer, the first and second annular free magnetic layers separated by a non-magnetic separator layer and an annular tunnel insulator disposed about the first and second of annular free magnetic layers and the non-magnetic separator layer;

a first planar reference magnetic layer disposed about the plurality of annular structures and separated from the respective first annular free magnetic layers of each of the plurality of annular structures by the respective annular tunnel insulator of each of the plurality of annular structures and the first planar reference magnetic layer aligned with the first annular free magnetic layer;

a first non-magnetic insulator layer disposed about the plurality of annular structures and on a first side of the first planar reference magnetic layer;

a second non-magnetic insulator layer disposed about the plurality of annular structures and on a second side of the first planar reference magnetic layers;

a second planar reference magnetic layer disposed about the plurality of annular structures and separated from the respective second annular free magnetic layers of each of the plurality of annular structures by the respective annular tunnel insulator of each of the plurality of annular structures, and the second planar reference magnetic layer aligned with the second annular free magnetic layer;

a third non-magnetic insulator layer disposed about the plurality of annular structures and between the second non-magnetic insulator layer and a first side of the second planar reference magnetic layer; and

a fourth non-magnetic insulator layer disposed about the plurality of annular structures and on a second side of the second planar reference magnetic layer.

2. The device of claim 1 , further comprising:

each of the plurality of annular structures including a third annular free magnetic layer disposed about the annular non-magnetic layer, the third annular free magnetic layer separated from the second annular free magnetic layer by a second non-magnetic separator layer;

a third planar reference magnetic layer disposed about the plurality of annular structures and separated from the respective third annular free magnetic layers of each of the plurality of annular structures by the respective annular tunnel insulator of each of the plurality of annular structures, and the third planar reference magnetic layer aligned with the third annular free magnetic layer;

a fifth non-magnetic insulator layer disposed about the plurality of annular structures and between the fourth non-magnetic insulator layer and a first side of the third planar reference magnetic layer; and

a sixth non-magnetic insulator layer disposed about the plurality of annular structures and on a second side of the third planar reference magnetic layer.

3. The device of claim 1 , further comprising:

a non-magnetic metal layer disposed between the second non-magnetic insulator layer and the third non-magnetic insulator layer.

4. The device of claim 1 , wherein the plurality of non-magnetic separator layers comprise an oxide alloy including Cobalt-Iron-Boron (Co—Fe—B) and a non-magnetic material selected from the group consisting of Copper (Cu), Aluminum (Al), and Ruthenium (Ru).

5. The device of claim 1 , wherein each annular structure comprises a conical structure including a conical non-magnetic layer disposed about a conical portion of the conductive layer, first and second conical free magnetic layers disposed about the conical non-magnetic layer, and a conical tunnel insulator disposed about the first and second conical free magnetic layers.

6. The device of claim 5 , wherein each conical structure has a taper of approximately 10-45 degrees.

7. The device of claim 1 , further comprising;

the plurality of annular structures arranged in columns and rows in the first and second planar reference magnetic layers; and

a plurality of insulator regions disposed in the first and second planar reference magnetic layers between a respective pair of columns of the plurality of annular structures.

8. The device of claim 1 , wherein,

a magnetic field of the first and second planar reference magnetic layers has a fixed polarization substantially perpendicular to a major planar orientation of the first and second planar reference magnetic layers; and

a magnetic field of the annular free magnetic layer of each of the plurality of annular structures has a polarization substantially perpendicular to the major planar orientation of the first and second planar reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first and second planar reference layers.

9. The device of claim 8 , wherein,

the magnetic field of the first and second annular free magnetic layers of each of the plurality of annular structures is configured to switch to being substantially parallel to the magnetic field of the first and second planar reference magnetic layers in response to a current flow in a first direction through the respective conductive annular layer of the plurality of annular structures and to switch to being substantially anti-parallel to the magnetic field of the first and second planar reference magnetic layers in response to a current flow in a second direction through the respective conductive annular layer of the plurality of annular structures.

10. A memory device, comprising:

an array of Magnetic Tunnel Junction (MJT) cells including;

a plurality of annular structures arranged in columns and rows, each annular structure including an annular non-magnetic layer disposed about an annular conductive layer, a plurality of annular free magnetic layers disposed about the annular non-magnetic layer, the plurality of annular free magnetic layers separated from each other by corresponding ones of a plurality of non-magnetic separator layers, and an annular tunnel insulator disposed about the respective annular free magnetic layers;

a plurality of planar reference magnetic layers disposed about the respective annular tunnel insulator of each of the plurality of annular structures and aligned with corresponding ones of the plurality of annular free magnetic layers;

a first plurality of non-magnetic insulator layers disposed about the plurality of annular structures and on a first side of corresponding ones of the plurality of planar reference magnetic layers: and

a second plurality of non-magnetic insulator layers disposed about the plurality of annular structures and on a second side of corresponding ones of the plurality of planar reference magnetic layers; and

a planar non-magnetic conductive layer disposed between adjacent ones of the first plurality of non-magnetic insulator layers and the second plurality of non-magnetic insulator layers.

11. The memory device of claim 10 , wherein,

a magnetic field of the plurality of planar reference magnetic layers has a fixed polarization substantially perpendicular to a major planar orientation of the plurality of planar reference magnetic layers; and

a magnetic field of the plurality of annular free magnetic layers of each of the plurality of annular structures has a polarization substantially perpendicular to the major planar orientation of the plurality of planar reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the plurality of planar reference layers.

12. The memory device of claim 11 , wherein,

the magnetic field of the plurality of annular free magnetic layers of each of the plurality of annular structures is configured to switch to being substantially parallel to the magnetic field of the plurality of planar reference layers in response to a current flow in a first direction through the respective conductive annular layer of the plurality of annular structures and to switch to being substantially anti-parallel to the magnetic field of the plurality of planar reference layers in response to a current flow in a second direction through the respective conductive annular layer of the first plurality of annular structures.

13. The memory device of claim 10 , further comprising:

the plurality of annular structures arranged in columns and rows in the plurality of planar reference magnetic layers: and

a plurality of insulator regions disposed in the plurality of planar reference magnetic layers between a respective pair of columns of the plurality of annular structures.

14. A memory device comprising:

an array of Magnetic Tunnel Junction (TS) cells arranged in cell columns and cell rows in a plurality of cell levels, wherein the MTJ cells in corresponding cell column and cell row positions in the plurality of cell levels are coupled together in cell strings, the MTJ cells in each cell string include;

an annular structure including an annular non-magnetic layer disposed about an annular conductive layer, a plurality of annular free magnetic layers disposed about the annular non-magnetic layer, the annular free magnetic layer separated from each other by corresponding ones of a plurality of non-magnetic separator layers, and an annular tunnel insulator disposed about the plurality of annular free magnetic layers;

a portion of corresponding ones of planar reference magnetic layers disposed about the annular structure and aligned with corresponding ones of the plurality of portions of the annular free magnetic layers;

a portion of one or more planar non-magnetic insulator layers disposed on a first side of each of the plurality of planar reference magnetic layers and about the annular structure;

a portion of one or more other planar non-magnetic insulator layers disposed on a second side of each of the plurality of planar reference magnetic layers and about the annular structure; and

a plurality of select elements arranged in select columns and select rows, wherein respective select elements are coupled to respective strings of MTJ cells in corresponding cell column and cell row positions.

15. The memory device of claim 14 , further comprising:

a plurality of blocks of the array of cells arranged in block columns and block rows.

16. The memory device of claim 14 , wherein the annular structure comprises a conical structure including a conical non-magnetic layer disposed about a conical portion of the conductive layer, a plurality of conical free magnetic layers disposed about the conical non-magnetic layer, and a conical tunnel insulator disposed about the plurality of conical free magnetic layers.

17. The memory device of claim 14 , wherein,

a magnetic field of the planar reference magnetic layers have a fixed polarization substantially perpendicular to a major planar orientation of the planar reference magnetic layers; and

a magnetic field of the plurality of annular free magnetic layers have a polarization substantially perpendicular to the major planar orientation of the planar reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the planar reference layers.

18. The memory device of claim 17 , wherein the magnetic field of the plurality of annular free magnetic layers is configured to switch to being substantially parallel to the magnetic field of the plurality of planar reference layers in response to a current flow in a first direction through the conductive annular layer and to switch to being substantially anti-parallel to the magnetic field of the plurality of planar reference layers in response to a current flow in a second direction through the conductive annular layer.