1. A magnetic memory element comprising:
a first magnetization free layer configured to be formed of a ferromagnetic material having perpendicular magnetic anisotropy;
a second magnetization free layer configured to be provided near said first magnetization free layer and formed of a ferromagnetic material having in-plane magnetic anisotropy;
a reference layer configured to be formed of a ferromagnetic material having in-plane magnetic anisotropy; and
a non-magnetic layer configured to be provided between said second magnetization free layer and said reference layer,
wherein said first magnetization free layer includes:
a first magnetization fixed region of which magnetization is fixed,
a second magnetization fixed region of which magnetization is fixed, and
a magnetization free region which is connected to said first magnetization fixed region and said second magnetization fixed region, and of which magnetization can be switched,
wherein said first magnetization free layer has a first surface and said second magnetization free layer has a second surface,
wherein a whole of said second surface is opposed to a portion less than a whole of said first surface, and
wherein said second magnetization free layer is provided in a first direction away from said magnetization free region.
2. The magnetic memory element according to claim 1, wherein said reference layer has magnetization fixed in a direction approximately parallel to said first direction.
3. The magnetic memory element according to claim 1, wherein said second magnetization free layer is included in one of said first magnetization fixed region and said second magnetization fixed region.
4. The magnetic memory element according to claim 3, wherein said first magnetization fixed region, said magnetization free region and said second magnetization fixed region are arranged linearly in this order, and
wherein said first magnetization free layer has a rectangle shape with an aspect ratio of approximately three.
5. The magnetic memory element according to claim 3, further comprising:
a magnetization fixed layer group configured to be magnetically coupled with said first magnetization free layer.
6. The magnetic memory element according to claim 3, further comprising:
a conductive layer configured to be electrically connected to said first magnetization free layer and one of said second magnetization free layer and said reference layer.
7. The magnetic memory element according to claim 5, wherein said second magnetization free layer and said magnetization fixed layer group are arranged in places opposite to each other with respect said first magnetization free layer.
8. The magnetic memory element according to claim 5, wherein said second magnetization free layer and said magnetization fixed layer group are arranged in the same side with respect said first magnetization free layer.
9. A magnetic memory comprising:
a plurality of magnetic memory cells configured to be arranged in a matrix shape, each of plurality of magnetic memory cells including a magnetic memory element,
wherein said magnetic memory element comprising:
a first magnetization free layer configured to be formed of a ferromagnetic material having perpendicular magnetic anisotropy;
a second magnetization free layer configured to be provided near said first magnetization free layer and formed of a ferromagnetic material having in-plane magnetic anisotropy;
a reference layer configured to be formed of a ferromagnetic material having in-plane magnetic anisotropy; and
a non-magnetic layer configured to be provided between said second magnetization free layer and said reference layer,
wherein said first magnetization free layer includes:
a first magnetization fixed region of which magnetization is fixed,
a second magnetization fixed region of which magnetization is fixed, and
a magnetization free region which is connected to said first magnetization fixed region and said second magnetization fixed region, and of which magnetization can be switched,
wherein said first magnetization free layer has a first surface and said second magnetization free layer has a second surface,
wherein a whole of said second surface is opposed to a portion less than a whole of said first surface, and
wherein said second magnetization free layer is provided in a first direction away from said magnetization free region.
10. The magnetic memory according to claim 9, wherein said reference layer has magnetization fixed in a direction approximately parallel to said first direction.
11. The magnetic memory according to claim 9, wherein said second magnetization free layer is included in one of said first magnetization fixed region and said second magnetization fixed region.
12. The magnetic memory according to claim 11, wherein said first magnetization fixed region, said magnetization free region and said second magnetization fixed region are arranged linearly in this order, and
wherein said first magnetization free layer has a rectangle shape with an aspect ratio of approximately three.
13. The magnetic memory according to claim 11, wherein said magnetic memory element further includes:
a magnetization fixed layer group configured to be magnetically coupled with said first magnetization free layer.
14. The magnetic memory according to claim 11, wherein said magnetic memory element further includes:
a conductive layer configured to be electrically connected to said first magnetization free layer and one of said second magnetization free layer and said reference layer.
15. The magnetic memory according to claim 13, wherein said second magnetization free layer and said magnetization fixed layer group are arranged in places opposite to each other with respect said first magnetization free layer.
16. The magnetic memory according to claim 13, wherein said second magnetization free layer and said magnetization fixed layer group are arranged in the same side with respect said first magnetization free layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A bone fixation system, comprising:
a plate having a top and bottom surface and a central axis extending longitudinally between a first end and a second end, said plate having a plurality of openings between said top and bottom surfaces, wherein a pair of said openings are first and second slots positioned on opposing sides of said central axis, said first and second slots each having a width transverse to said central axis and a length extending between first and second ends of said slot in the direction of said central axis, said length being greater than said width; and
a drill guide having first and second guide members extending from a handle, said first and second guide members each having a passage therethrough opening at a distal end of said corresponding guide member, wherein each of said guide members includes an offset portion adjacent said distal end positionable in a corresponding one of said first and second slots against said first end of said corresponding slot, wherein each of said offset portions is configured to space said first end of said corresponding slot from an adjacent edge of a hole formed through said guide member such that a fastener inserted into the hole through said slot is spaced a distance from said first end of said slot.
2. The bone fixation system of claim 1, wherein each of said first and second slots defines a recess adjacent said top surface of said plate.
3. The bone fixation system of claim 2, wherein each of said guide members includes an intermediate portion configured to reside in said recess.
4. The bone fixation system of claim 1, wherein each of said guide members has a slot engaging end extending proximally from said distal end and positionable in said corresponding slot in contact with sidewalls of said slot.
5. The bone fixation system of claim 1, wherein said plate defines a groove in said top surface extending longitudinally along said central axis of said plate, said groove overlapping each of said first and second slots.
6. The bone fixation system of claim 5, wherein each of said guide members includes a notched medial sidewall oriented toward said groove when said drill guide is positioned on said plate.
7. The bone fixation system of claim 1, wherein said first and second slots are positioned over an upper vertebrae when said plate is located on the spinal column.
8. The bone fixation system of claim 1, wherein:
each of said guide members includes a main body portion extending from said handle towards said distal end, said main body portion having an outer surface extending thereabout; and
said offset portion of each of said guide members has a contact surface positionable against said corresponding first end of said slot, said contact surface lying in the same plane as and forming an extension of a portion of said outer surface of said main body portion.
9. The bone fixation system of claim 8, wherein each of said guide members has a slot engaging portion extending proximally from said distal end, an intermediate portion extending between said slot engaging portion and said main body portion, said main body portion having a first width, said intermediate portion having a second width less than said first width, and said slot engaging end having a third width less than said second width.
10. The bone fixation system of claim 9, wherein said contact surface extends along said slot engaging portion and said intermediate portion.
11. The bone fixation system of claim 1, wherein said distance is 1 millimeter or more.
12. A drill guide for drilling a hole in a bone through a bone plate having at least one slot formed therethrough for receiving a bone engaging fastener, the slot having a length and a width transverse to and less than the length, the length extending between opposite first and second ends of the slot, the drill guide comprising:
a handle; and
at least one guide member extending from said handle, said at least one guide member having a passage extending between a distal end and a proximal end of said drill guide, wherein said at least one guide member includes an offset portion adjacent said distal end positionable against the first end of the slot, wherein said offset portion is configured to space the first end of the slot from an adjacent edge of a hole formed through said guide member in the bone such that a fastener inserted through the slot into the drilled hole is spaced a distance from the first end of the slot.
13. The drill guide of claim 12, wherein said at least one guide member includes first and second guide members extending from said handle.
14. The drill guide of claim 13, wherein said handle includes:
a connecting member coupled to proximal ends of said first and second guide members;
a shaft extending proximally from said connecting portion; and
a gripping portion coupled to a proximal end of said shaft.
15. The drill guide of claim 13, wherein said second guide member includes a passage extending between a proximal end and a distal end, each of said first and second guide members has a central axis extending through said passage, said central axes intersecting at a point distally of said distal ends and forming an angle therebetween.
16. The drill guide of claim 12, wherein:
said guide member includes a main body portion extending from said handle toward said distal end, said main body portion having an outer surface extending thereabout; and
said offset portion has a contact surface positionable against the first end of the slot, said contact surface lying in the same plane as and forming an extension of a portion of said outer surface of said main body portion.
17. The bone fixation system of claim 16, wherein said guide member has a slot engaging portion extending proximally from said distal end, an intermediate portion extending between said slot engaging portion and said main body portion, said main body portion having a first width, said intermediate portion having a second width less than said first width, and said slot engaging end having a third width less than said second width.
18. The bone fixation system of claim 17, wherein said contact surface extends along said slot engaging portion and said intermediate portion.
19. The bone fixation system of claim 12 wherein said distance is 1 millimeter or more.
20. The drill guide of claim 12, wherein said guide member includes a notched sidewall.
21. A method for securing a plate to a portion of the spinal column, the spinal column portion including an upper vertebra and a lower vertebra, the method comprising:
providing a plate having a central axis extending between the upper and lower vertebra, the plate including at least one slot extending between a top surface and a bottom surface of the plate, the slot extending in the direction of the central axis between a first end and an opposite second;
placing the plate on the spinal column portion with the slot over the upper vertebra;
positioning a drill guide on the plate, the drill guide having an offset portion positionable in the slot against the first end of the slot; and
drilling a hole through the drill guide, wherein the offset portion of the drill guide spaces the adjacent edge of the drilled hole from the first end of the slot.
22. The method of claim 21, further comprising:
inserting a bone engaging fastener in the drilled hole, wherein the bone engaging fastener is spaced a distance from the first end of the slot; and
applying a compression load to the spinal column portion with a compression tool to position the bone engaging fastener more towards the second end of the slot.
23. The method of claim 21, further comprising:
inserting a bone engaging fastener into the drilled hole, wherein the bone engaging fastener is spaced a distance from the first end of the slot; and
allowing movement of the bone engaging fastener towards the first end of the slot in response to extension of the portion of the spinal column.
24. The method of claim 23, wherein the distance is based on a desired amount of extension of the portion of the spinal column.
25. The method of claim 24, wherein the distance is 1 millimeter or more.
26. The method of claim 21, further comprising fixing the plate to the lower vertebrae.