Granted Patent B2

US 7,635,903 · App. 11/225,973 · Granted Dec 22, 2009

Abstract

Claims (79)

1. A circuit comprising:

an oscillator comprising at least one of:

a parallel array of magnetoresistive contacts to at least one individualized area of at least one magnetoresistive film, each of the magnetoresistive contacts of the parallel array comprising a spin transfer oscillator; and

a series array of magnetoresistive contacts to individualized areas of at least one magnetoresistive film, each of the magnetoresistive contacts of the parallel array comprising a spin transfer oscillator;

one of a current or voltage source coupled to the oscillator.

2. The circuit of claim 1 wherein:

the oscillator comprises the parallel array of magnetoresistive contacts to the at least one individualized area of the at least one magnetoresistive film.

3. The circuit of claim 2 wherein:

the parallel array of magnetoresistive contacts further comprises:

a parallel array of ferromagnetic point contacts; and

the at least one individualized area of the at least one magnetoresistive film of the parallel array of magnetoresistive contacts further comprises:

a single magnetoresistive film.

4. The circuit of claim 1 wherein:

the oscillator comprises the series array of magnetoresistive contacts to the individualized areas of the at least one magnetoresistive film.

5. The circuit of claim 4 wherein:

the series array of magnetoresistive contacts further comprises: a series array of ferromagnetic point contacts; and

the individualized areas of the at least one magnetoresistive film comprises: discrete portions of a single magnetoresistive film.

6. The circuit of claim 1 wherein:

the at least one individualized area of the at least one magnetoresistive film and the individualized areas of the at least one magnetoresistive film are selected from the group consisting of a tunneling magnetoresistive film, a giant magnetoresistive film, and a colossal magnetoresistive film.

7. The circuit of claim 1 wherein:

the oscillator comprises the parallel array of magnetoresistive contacts and the series array of magnetoresistive contacts;

the parallel array of magnetoresistive contacts comprises a parallel array of N 1 magnetoresistive contacts;

N 1 is greater than 1;

the series array of magnetoresistive contacts comprises a series array of N 2 magnetoresistive contacts; and

N 2 is greater than 1.

8. The circuit of claim 7 wherein: N 2 is greater than N 1 .

9. The circuit of claim 7 further comprising:

an inductor coupled in series with the parallel array of N 1 magnetoresistive contacts and in parallel with the series array of N 2 magnetoresistive contacts; and

a resistor coupled in series with the parallel array of N 1 magnetoresistive contacts and in parallel with the series array of N 2 magnetoresistive contacts.

10. The circuit of claim 9 wherein:

an output power of the oscillator is increased by a factor approximately proportional to a sum of N 1 and N 2 as compared to a single contact to a magnetoresistive film.

11. The circuit of claim 7 wherein:

the oscillator further comprises N 1 minus one of the series array of N 2 magnetoresistive contacts in addition to the series array of N 2 magnetoresistive contacts; and

the N 1 minus one of the series array of N 2 magnetoresistive contacts are in parallel with the series array of N 2 magnetoresistive contacts and are in series with the parallel array of N 1 magnetoresistive contacts.

12. The circuit of claim 11 wherein:

an output power of the oscillator is increased by a factor approximately proportional to N 1 times a sum of N 2 plus one as compared to a single contact to a magnetoresistive film.

13. The circuit of claim 1 wherein:

the oscillator comprises the parallel array of magnetoresistive contacts;

the parallel array of magnetoresistive contacts comprises a parallel array of N 1 magnetoresistive contacts;

the oscillator further comprises an additional N 2 minus one parallel arrays of N 1 magnetoresistive contacts;

N 1 is greater than 1;

N 2 is greater than 1; and

the N 2 parallel arrays of N 1 magnetoresistive contacts are in series with each other.

14. The circuit of claim 13 wherein:

an output power of the oscillator is increased by a factor approximately proportional to N 1 multiplied by N 2 as compared to a single contact to a magnetoresistive film.

15. A spin-transfer oscillator comprising:

a parallel array of N 1 ferromagnetic point contacts to at least one portion of at least one magnetoresistive film; and

a series array of N 2 ferromagnetic point contacts to separated portions of at least one magnetoresistive film, wherein:

an output frequency of the spin-transfer oscillator is frequency tunable as a function of one of an applied voltage, current, or magnetic field;

N 1 is greater than 1;

N 2 is greater than 1;

portions of the at least one magnetoresistive film are located under the N 1 ferromagnetic point contacts and are coupled together by direct magnetic coupling; and

portions of the at least one magnetoresistive film are located under the N 2 ferromagnetic point contacts and are coupled together by injection current locking.

16. The spin-transfer oscillator of claim 15 wherein:

the at least one magnetoresistive film of the parallel array of N 1 ferromagnetic point contacts is a first portion of a single magnetoresistive film; and

the at least one magnetoresistive film of the series array of N 2 ferromagnetic point contacts is a second portion of the single magnetoresistive film.

17. The spin-transfer oscillator of claim 16 further comprising:

an inductor coupled in series with the parallel array of N 1 ferromagnetic point contacts; and

a resistor coupled in series with the inductor and the parallel array of N 1 ferromagnetic point contacts, wherein:

the series array of N 2 ferromagnetic point contacts is in series with the parallel array of N 1 ferromagnetic point contacts and is in parallel with the inductor and the resistor; and

an output power of the spin-transfer oscillator is increased by a factor approximately proportional to (N 1 +N 2 ) as compared to a single contact to the single magnetoresistive film.

18. The spin-transfer oscillator of claim 16 further comprising:

(N 1 −1) of the series array of N 2 ferromagnetic point contacts to the separated portions of the at least one magnetoresistive film, in addition to the series array of N 2 ferromagnetic point contacts to the separated portions of the at least one magnetoresistive film, wherein:

the (N 1 −1) of the series array of N 2 ferromagnetic point contacts are in parallel with each other;

the (N 1 −1) of the series array of N 2 ferromagnetic point contacts are in parallel with the series array of N 2 ferromagnetic point contacts;

the (N 1 −1) of the series array of N 2 ferromagnetic point contacts and the series array of N 2 ferromagnetic point contacts are in series with the parallel array of N 1 ferromagnetic point contacts; and

an output power of the spin-transfer oscillator is increased by a factor approximately proportional to (N 1 ×(N 2 +1)) as compared to a single contact to the single magnetoresistive film.

19. The spin-transfer oscillator of claim 18 wherein: N 2 is greater than N 1 .

20. A spin-transfer oscillator comprising:

N 2 parallel arrays of N 1 ferromagnetic point contacts to at least one portion of at least one magnetoresistive film, wherein:

N 1 is greater than 1;

N 2 is greater than 1;

the N 2 parallel arrays of N 1 ferromagnetic point contacts are in series with each other;

an output frequency of the spin-transfer oscillator is frequency tunable as a function of one of an applied voltage, current, or magnetic field; and

an output power of the spin-transfer oscillator is increased by a factor approximately proportional to (N 1 ×N 2 ) as compared to a single contact to the at least one magnetoresistive film.

21. The spin-transfer oscillator of claim 20 wherein:

the at least one magnetoresistive film of the N 2 parallel array of N 1 ferromagnetic point contacts is a single magnetoresistive film.

22. The spin-transfer oscillator of claim 21 wherein:

N 2 is greater than N 1 .

Assignments (13)