Thermocooling of GMR sensors

1. A thermoelectrically cooled GMR sensor comprising:

a. a first thermoelectric layer comprising an array of nanowires, wherein the nanowires include a diameter of about 1 nanometer to about 1000 nanometers;

b. a plurality of alternating layers of magnetic and nonmagnetic material positioned over and extending the nanowires to form a GMR assembly;

c. a second thermoelectric layer positioned over the GMR assembly and extending the nanowires, such that the nanowires have a length of between about 100 nanometers and about 500 microns; and

d. conductors in contact with the first and second thermoelectric layers for connecting the thermoelectric layers to a voltage source.

2. The GMR sensor of claim 1 , wherein the nanowire diameters are between about 20 nanometers to about 100 nanometers and the nanowire lengths are between about 5 microns to and about 60 microns.

3. The GMR sensor of claim 1 , further comprising at least 500 alternating layers of magnetic and nonmagnetic material.

4. The GMR sensor of claim 3 , further comprising between about 2000 and about 2500 alternating layers of magnetic and nonmagnetic material.

5. The GMR sensor of claim 1 , wherein said GMR assembly is positioned directly on said first thermoelectric layer and said second thermoelectric layer is positioned directly on said GMR assembly.

6. The GMR sensor of claim 1 , wherein a cross-sectional area of the layers forming the array of nanowires is about 0.001 nm 2 to about 1 mm 2 .

7. The GMR sensor of claim 1 , wherein the array of nanowires has a needle density of about 10 5 to 10 10 wires/cm 2 .

8. The GMR sensor of claim 1 , wherein the nanowires have an aspect ratio (length/diameter) of at least about 1000.

9. The GMR sensor of claim 1 , wherein the thermoelectric layers consist essentially of Bi x Te y compounds.

10. The GMR sensor of claim 1 , wherein the diameter of the nanowires have a tolerance of between about 1 nm.

11. The GMR sensor of claim 1 , wherein the diameter of the nanowires have a tolerance of less than about 5 nm.

12. A method of forming a thermoelectrically cooled GMR sensor comprising the steps of:

a. electrodepositing a first thermoelectric layer comprising one of a p-type material or an n-type material from a first solution containing Bi, Sb, and Te under a first set of conditions;

b. electrodepositing onto the first thermoelectric layer a plurality of alternating layers of magnetic and non-magnetic materials in order to form a GMR assembly;

c. electrodepositing a second thermoelectric layer comprising the other of a p-type or an n-type material on the GMR assembly from the first solution under a second set of conditions; and

d. forming conductive layers in electrical contact with the thermoelectric layers.

13. The method of claim 12 , wherein an electropotential applied during deposition of the p-type material is about −100 to about −350 mV and an electropotential applied during deposition of the n-type material is about −20 to −200 mV.

14. The method of claim 12 , wherein the electrodeposition steps are carried out at approximately standard (ambient) temperature and pressure.

15. The method of claim 13 , wherein the first solution further includes Sb and the p-type material has the formulation Bi 0.5 Sb 1.5 Te 3 and the n-type material has the formulation Bi 2 Sb 0.3 Te 2.7 .

16. The method of claim 12 , wherein the first thermoelectric layer is formed on a template having apertures of exposed conductive material ranging from 10 nm to 500 um.

17. The method of claim 16 , wherein the template is between 1 um and 500 um in thickness.

18. The method of claim 12 , wherein the deposition is carried out at any sub-range between −1 mV and about −400 mV.

19. The method of claim 12 , wherein the electropotential applied during deposition of the p-type material is a first negative value and the electropotential applied during deposition of the n-type material is a second negative value less than said first value.