SPIN CURRENT GENERATION WITH NANO-OSCILLATOR

• US 20160142012A1
• Filed: 11/13/2014
• Published: 05/19/2016
• Est. Priority Date: 11/13/2014
• Status: Active Grant

• Current Assignee: Regents of The University of Minnesota (University of Minnesota)
• Original Assignee: Regents of The University of Minnesota (University of Minnesota)
• Inventors: Wang, Jian-Ping, Jamali, Mahdi
• Granted Patent: US 9,425,738 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3958 the active elements being arranged in a single plane, e.g. "matrix" disposition
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 19/0808 using magnetic domain propagation
• CPC Class Codes: G11C 19/0841 using electric current
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H03B 15/006 using spin transfer effects or giant magnetoresistance
• CPC Class Codes: H03K 19/16 using saturable magnetic devices
• CPC Class Codes: H03K 19/18 using galvano-magnetic devices, e.g. Hall-effect devices
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A device including a spin channel to transport a spin current, a nano-oscillator, and a magnetoresistive device that receives the spin current from the nano-oscillator. The nano-oscillator includes a magnetization state that oscillates between a first state and a second state in response to an input voltage or current. The oscillation of the nano-oscillator may induce the spin current within the spin channel. The magnetoresistive device includes a magnetization state that is set based at least in part on the received spin current.

Claims

1. A device comprising:

a spin channel to transport a spin current;

a nano-oscillator having a magnetization state that, in response to a DC input voltage or current, oscillates between a first state and a second state and induces the spin current within the spin channel; and

a magnetoresistive device that receives the spin current from the nano-oscillator, the magnetoresistive device having a magnetization state that is set to a parallel or anti-parallel state by the received spin current.

2. The device of claim 1, wherein the nano-oscillator comprises an input magnetoresistive device, the input magnetoresistive device comprising one of:

a single magnetic layer;

or

multiple layers including a fixed magnetic layer, a free magnetic layer, and a non-magnetic layer.

3. The device of claim 2, wherein the thickness of the single magnetic layer or the free magnetic layer is between approximately 0.8 nanometers and approximately 6.0 nanometers.

4. The device of claim 1, wherein the magnetoresistive device receives the spin current from the spin channel in part by the drift of the spin current through the spin channel to the magnetoresistive device.

5. The device of claim 1, wherein the device further comprises a NOT gate.

6. The device of claim 1, wherein the nano-oscillator comprises a first nano-oscillator, the spin current comprises a first spin current, and the DC input voltage or current comprises a first input voltage or current, and wherein the device further comprises:

a second nano-oscillator having a magnetization state that, in response to a second input voltage or current, oscillates between a first state and a second state and induces a second spin current within the spin channel,

wherein the magnetoresistive device receives the second spin current from the second nano-oscillator by diffusion of the second spin current through the spin channel, wherein the magnetization state of the magnetoresistive device is set by the received first spin current and second spin current.

7. The device of claim 1, wherein a resistivity of the magnetoresistive device indicates the magnetization state of the magnetoresistive device and corresponds to a digital output value of the magnetoresistive device.

8. The device of claim 1, wherein the oscillation of the nano-oscillator between the first state and the second state is further based on one or more of voltage-controlled magnetic anisotropy (VCMA), strain induced magnetization switching, or exchange biasing magnetization switching.

9. A method comprising:

applying a DC input voltage or current to a nano-oscillator to oscillate a magnetization state of the nano-oscillator between a first state and a second state and induce a spin current in a spin channel coupled to the nano-oscillator; and

setting, in response to the spin current, a magnetization state of a magnetoresistive device coupled to the spin channel, wherein the magnetization state of the magnetoresistive device is set to one of a parallel or anti-parallel state by the received spin current.

10. The method of claim 9, wherein receiving an input voltage or current further comprises exciting magnetization dynamics in the nano-oscillator, wherein the oscillation of the nano-oscillator between the first state and the second state induces the spin current, wherein the spin current drifts through the spin channel from the nano-oscillator to the magnetoresistive device.

11. The method of claim 9, wherein exciting magnetization dynamics is further based on one or more of voltage-controlled magnetic anisotropy (VCMA), strain induced magnetization switching, or exchange biasing magnetization switching.

12. The method of claim 9, further comprising determining the magnetization state of the output magnetoresistive device.

13. The method of claim 9, wherein applying an input voltage or current comprises applying a first input voltage or current, the nano-oscillator comprises a first nano-oscillator, and the spin current comprises a first spin current, the method further comprising:

applying a second input voltage or current to a second nano-oscillator to oscillate a magnetization state of the second nano-oscillator between a first state and a second state and induce a second spin current in the spin channel coupled to the second nano-oscillator; and

setting, in response to the first spin current and second spin current, a magnetization state of a magnetoresistive device coupled to the spin channel.

14. A logic device comprising:

a spin channel to transport a spin current;

a nano-oscillator having a magnetization state that, in response to a DC input voltage or current, oscillates between a first state and a second state and induces the spin current within the spin channel;

a magnetoresistive device that receives the spin current from the nano-oscillator, the magnetoresistive device having a magnetization state that is set to a parallel or anti-parallel state based at least in part on the received spin current; and

a controller configured to measure a resistivity of the magnetoresistive device and output a voltage or current.

15. The logic device of claim 14, wherein the nano-oscillator comprises an input magnetoresistive device comprising one of:

a single magnetic layer;

or

multiple layers including a fixed magnetic layer, a free magnetic layer, and a non-magnetic layer.

16. The logic device of claim 15, wherein the thickness of the single magnetic layer or the free magnetic layer is between approximately 0.8 nanometers and approximately 6.0 nanometers.

17. The logic device of claim 14, wherein the magnetoresistive device receives the spin current from the spin channel in part by the drift of the spin current through the spin channel to the magnetoresistive device.

18. The logic device of claim 14, wherein the nano-oscillator comprises a first nano-oscillator, the spin current comprises a first spin current, and the input voltage or current comprises a first input voltage or current, and wherein the device further comprises:

a second nano-oscillator having a magnetization state that, in response to a second input voltage or current, oscillates between a first state and a second state and induces a second spin current within the spin channel,

wherein the magnetoresistive device receives the second spin current from the second nano-oscillator by diffusion of the second spin current through the spin channel, wherein the magnetization state of the magnetoresistive device is set based at least in part on the received first spin current and second spin current.

19. The logic device of claim 14, wherein the resistivity of the magnetoresistive device indicates the magnetization state of the magnetoresistive device, wherein the controller outputs a digital value that corresponds to the resistivity of the magnetoresistive device.

20. A method comprising:

applying DC input voltage or current to a nano-oscillator to oscillate a magnetization state of the nano-oscillator between a first state and a second state and induce a spin current in a spin channel coupled to the nano-oscillator;

applying a gate voltage or current to the spin-channel to amplify an input current received by the spin channel with the spin current; and

outputting the amplified current.