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Proposal for a Domain Wall Nano-Oscillator driven by Non-uniform Spin Currents.

Sharma S, Muralidharan B, Tulapurkar A - Sci Rep (2015)

Bottom Line: We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000.A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples.Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.

ABSTRACT
We propose a new mechanism and a related device concept for a robust, magnetic field tunable radio-frequency (rf) oscillator using the self oscillation of a magnetic domain wall subject to a uniform static magnetic field and a spatially non-uniform vertical dc spin current. The self oscillation of the domain wall is created as it translates periodically between two unstable positions, one being in the region where both the dc spin current and the magnetic field are present, and the other, being where only the magnetic field is present. The vertical dc spin current pushes it away from one unstable position while the magnetic field pushes it away from the other. We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000. A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples. Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

No MeSH data available.


Oscillatory waveform and region of occurence (a) Comparison of the oscillatory part of the numerical and the analytic solution of domain wall position vs time, under an external applied field of 10 kA/m. The spin current density for the numerical solution was taken to be 0.96 GA/m2. (b) The values of spin current and magnetic field depicting the region in which the oscillations happen.
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f2: Oscillatory waveform and region of occurence (a) Comparison of the oscillatory part of the numerical and the analytic solution of domain wall position vs time, under an external applied field of 10 kA/m. The spin current density for the numerical solution was taken to be 0.96 GA/m2. (b) The values of spin current and magnetic field depicting the region in which the oscillations happen.

Mentions: We now demonstrate the simulated results of the domain wall motion using the rigid wall approximation discussed above. The waveform derived in Eq. (6) is not an exact solution of the equations for the rigid domain wall, but matches fairly well with the numerics as shown in Fig. 2(a). The regime of operation of the device as shown in Fig. 2(b) demonstrates that we need a minimum magnitude of the spin current to compete against the magnetic field and hence result in the oscillations. This can be understood by analyzing the motion of the domain wall when it starts from deep inside either region, i.e., the region deep inside the region of zero or non-zero spin current.


Proposal for a Domain Wall Nano-Oscillator driven by Non-uniform Spin Currents.

Sharma S, Muralidharan B, Tulapurkar A - Sci Rep (2015)

Oscillatory waveform and region of occurence (a) Comparison of the oscillatory part of the numerical and the analytic solution of domain wall position vs time, under an external applied field of 10 kA/m. The spin current density for the numerical solution was taken to be 0.96 GA/m2. (b) The values of spin current and magnetic field depicting the region in which the oscillations happen.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588506&req=5

f2: Oscillatory waveform and region of occurence (a) Comparison of the oscillatory part of the numerical and the analytic solution of domain wall position vs time, under an external applied field of 10 kA/m. The spin current density for the numerical solution was taken to be 0.96 GA/m2. (b) The values of spin current and magnetic field depicting the region in which the oscillations happen.
Mentions: We now demonstrate the simulated results of the domain wall motion using the rigid wall approximation discussed above. The waveform derived in Eq. (6) is not an exact solution of the equations for the rigid domain wall, but matches fairly well with the numerics as shown in Fig. 2(a). The regime of operation of the device as shown in Fig. 2(b) demonstrates that we need a minimum magnitude of the spin current to compete against the magnetic field and hence result in the oscillations. This can be understood by analyzing the motion of the domain wall when it starts from deep inside either region, i.e., the region deep inside the region of zero or non-zero spin current.

Bottom Line: We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000.A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples.Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.

ABSTRACT
We propose a new mechanism and a related device concept for a robust, magnetic field tunable radio-frequency (rf) oscillator using the self oscillation of a magnetic domain wall subject to a uniform static magnetic field and a spatially non-uniform vertical dc spin current. The self oscillation of the domain wall is created as it translates periodically between two unstable positions, one being in the region where both the dc spin current and the magnetic field are present, and the other, being where only the magnetic field is present. The vertical dc spin current pushes it away from one unstable position while the magnetic field pushes it away from the other. We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000. A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples. Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

No MeSH data available.