1. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said first layer of magnetic shielding includes a first magnetic field limiting material,
said second layer of magnetic shielding includes a second magnetic field limiting material, and
at least one said first magnetic field limiting material said second magnetic field limiting material is a magnetic field blocking material.
2. The card of claim 1, further comprising a battery.
3. The card of claim 1, further comprising a processor.
4. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said first layer of magnetic shielding includes a first magnetic field limiting material,
said second layer of magnetic shielding includes a second magnetic field limiting material, and
at least one of said first magnetic field limiting material and said second magnetic field limiting material is a magnetic material.
5. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said first layer of magnetic shielding includes a first magnetic field limiting material,
said second layer of magnetic shielding includes a second magnetic field limiting material,
said electronic device is a magnetic emulation circuit, and
said first layer of magnetic shielding and said second layer of magnetic shielding are configured to limit a portion of a magnetic field generated by said magnetic emulation circuit.
6. The card of claim 5, further comprising a plurality of displays.
7. The card of claim 5, further comprising:
a radio frequency identification (RFID) antenna; and
an integrated circuit chip (IC Chip).
8. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said electronic device is an emulator,
at least one of said first layer of magnetic shielding and said second layer of magnetic shielding is configured to limit a magnetic field generated by said emulator in a first region of said card,
said first layer of magnetic shielding and said second layer of magnetic shielding are configured to pass said magnetic field in a second region of said card, and
a magnitude of the magnetic field external to said card adjacent to said second region is greater than a magnitude of said magnetic field external to said card adjacent to said first region.
9. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said first layer of magnetic shielding includes a first magnetic field limiting material,
said second layer of magnetic shielding includes a second magnetic field limiting material,
said electronic device extends through a first region of said card and a second region of said card,
at least one of said first magnetic field limiting material and said second magnetic field limiting material is on said electronic device in a direction perpendicular to a surface of said card in said first region, and
said first magnetic field limiting material and said second magnetic field limiting material are not on said electronic device in said direction perpendicular to said surface of said card in said second region.
10. The card of claim 9, further comprising a plurality of displays.
11. The card of claim 9, further comprising:
a radio frequency identification (RFID) antenna; and
an integrated circuit chip (IC Chip).
12. A card comprising:
an electronic device operable to communicate information to a magnetic stripe reader;
a first layer of magnetic shielding, wherein said first layer of magnetic shielding is located over said electronic device; and
a second layer of magnetic shielding, wherein said second layer of magnetic shielding is located over said electronic device, wherein said second layer is located at a point above said first layer,
wherein said first layer of magnetic shielding includes a first magnetic field limiting material,
said second layer of magnetic shielding includes a second magnetic field limiting material,
said electronic device extends through a first region of said card and a second region of said card,
at least one of said first magnetic field limiting material and said second magnetic field limiting material is between said electronic device and a surface of said card in said first region,
said first magnetic field limiting material and said second magnetic field limiting material are not between said electronic device and said surface of said card in the second region,
said electronic device is operable to generate a magnetic field in said first and second regions,
a portion of said magnetic field generated in said second region is detectable by a read-head external to said card, and
a portion of said magnetic field generated in said first region is undetectable by said read-head.
13. A card comprising:
a first electronic device operable to communicate information to a magnetic stripe reader;
a first magnetic field limiting layer;
a second electronic device; and
a second magnetic field limiting layer,
wherein the first magnetic field limiting layer and the second magnetic field limiting layer are on opposite sides of the first electronic device, and
at least one of the first magnetic field limiting layer and the second magnetic field limiting layer separates the first electronic device and the second electronic device.
14. A card comprising:
a first electronic device operable to communicate information to a magnetic stripe reader;
a first magnetic field limiting layer;
a second electronic device; and
a second magnetic field limiting layer,
wherein the first magnetic field limiting layer and the second magnetic field limiting layer are on opposite sides of the first electronic device,
at least one of the first magnetic field limiting layer and the second magnetic field limiting layer is between the first electronic device and the second electronic device,
the first electronic device is operable to communicate with a first read-head,
the second electronic device is operable to communicate with a second read-head, and
the first electronic device is operable to communicate with the first read head while the second electronic device communicates with the second read head.
15. The card of claim 13, further comprising a plurality of displays.
16. The card of claim 13, further comprising:
a radio frequency identification (RFID) antenna; and
an integrated circuit chip (IC Chip).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A magnetic tunnel junction (MTJ), comprising:
a first electrode and a second electrode;
a tunnel barrier between the first and second electrodes;
a free synthetic antiferromagnet (SAF) between the first electrode and the tunnel barrier;
a fixed layer between the tunnel barrier and the second electrode;
wherein the free SAF comprises:
a first layer and a second layer, wherein the first and second layers are ferromagnetic;
a third layer between the first and second layers, wherein the third layer comprises a base material;
a fourth layer between the third layer and the second layer, wherein the fourth layer comprises tantalum.
2. The MTJ of claim 1, further comprising a fifth layer between the fourth and the second layer, wherein the fifth layer comprises a ferromagnetic material different from that used to form the second layer.
3. The MTJ of claim 2, wherein the fifth layer comprises at least one of cobalt and iron.
4. The MTJ of claim 3, wherein the fourth layer and the fifth layer are substantially merged.
5. The MTJ of claim 1, wherein the base material comprises ruthenium.
6. An MTJ, comprising:
a first electrode and a second electrode;
a tunnel barrier between the first and second electrodes;
a free synthetic antiferromagnet (SAF) between the first electrode and the tunnel barrier;
a fixed layer between the tunnel barrier and the second electrode;
wherein the free SAF comprises:
a first layer and a second layer, wherein the first and second layers are ferromagnetic;
a third layer between the first and second layers, wherein the third layer comprises first material and a second material wherein the first material is one of ruthenium, rhodium, iridium, and osmium and the second material is one of boron, aluminum, carbon, tantalum, niobium, molybdenum, zirconium, and hafnium.
7. The MTJ of claim 6, wherein the first material and the second material form an alloy.
8. The MTJ of claim 7, wherein the first material comprises ruthenium and the second material comprises one of tantalum and boron.
9. The MTJ of claim 8, wherein the second material is boron.
10. The MTJ of claim 6, wherein the third layer comprises a fourth layer of the first material and a fifth layer of the second material.
11. The MTJ of claim 10, wherein the fourth layer comprises ruthenium and the fifth layer comprises tantalum.
12. The MTJ of claim 11, wherein the fifth layer further comprises at least one of cobalt and iron.
13. The MTJ of claim 11, wherein, the fourth layer is between the fifth layer and the first layer, and further comprising a sixth layer of the first material between the fifth layer and the second layer.
14. The MTJ of claim 13, further comprising a seventh layer of the second material between the sixth layer and the second layer.
15. An MTJ, comprising:
a first electrode and a second electrode;
a tunnel barrier between the first and second electrodes;
a free synthetic antiferromagnet (SAF) between the first electrode and the tunnel barrier;
a fixed layer between the tunnel barrier and the second electrode;
wherein the free SAF comprises:
a first layer and a second layer, wherein the first and second layers are ferromagnetic;
a third layer of a first material between the first and second layers, wherein the first material is a base material;
a fourth layer of a second material between the third layer and the second layer, wherein the second material is selected from nickel-iron, cobalt-iron, tantalum, and aluminum; and
a fifth layer of the first material between the fourth layer and the second layer.
16. The MTJ of claim 15, further comprising:
a sixth layer of the second material between the fifth layer and the second layer; and
a seventh layer of the first material between the sixth layer and the second layer.
17. The MTJ of claim 15, wherein the second material comprises at least one of nickel and iron.
18. The MTJ of claim 15, wherein the second material comprises at least one of cobalt and iron.
19. The MTJ of claim 15, wherein the first layer comprises a nickel-iron alloy.
20. The MTJ of claim 19, wherein the nickel-iron alloy is about 16 to 20 atomic percent iron.
21. The MTJ of claim 20, wherein the second ferromagnetic layer comprises nickel iron that is about 18 atomic percent iron.
22. A magnetic tunnel junction (MTJ), comprising:
a first electrode and a second electrode;
a tunnel barrier between the first and second electrodes;
a free synthetic antiferromagnet (SAF) between the first electrode and the tunnel barrier;
a fixed layer between the tunnel barrier and the second electrode;
wherein the free SAF comprises:
a first layer and a second layer, wherein the first and second layers are ferromagnetic;
a third layer between the first and second layers, wherein the third layer comprises a base material;
a fourth layer that is conductive between the third layer and the second layer; and
a fifth layer between the fourth layer and the second layer, wherein the fifth layer comprises at least one of cobalt and iron.