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Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators.

Locatelli N, Hamadeh A, Abreu Araujo F, Belanovsky AD, Skirdkov PN, Lebrun R, Naletov VV, Zvezdin KA, Muñoz M, Grollier J, Klein O, Cros V, de Loubens G - Sci Rep (2015)

Bottom Line: This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures.We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators.Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.

View Article: PubMed Central - PubMed

Affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France.

ABSTRACT
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.

No MeSH data available.


(a) Illustration of the synchronized motion of the two auto-oscillating vortices cores, and of their net in-plane magnetizations (black arrows), for the cases of identical polarities (left) and opposite polarities (right) during one period. The sign of the associated dipolar coupling energy Wint is also given. (b) Predicted evolution of the dipolar coupling energy Wint versus part of oscillation period for identical (blue) and opposite polarities (red). The dotted lines show the average interaction energy in both cases.
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f4: (a) Illustration of the synchronized motion of the two auto-oscillating vortices cores, and of their net in-plane magnetizations (black arrows), for the cases of identical polarities (left) and opposite polarities (right) during one period. The sign of the associated dipolar coupling energy Wint is also given. (b) Predicted evolution of the dipolar coupling energy Wint versus part of oscillation period for identical (blue) and opposite polarities (red). The dotted lines show the average interaction energy in both cases.

Mentions: To gain further insight on the relative efficiency of the dipolar action for synchronization depending on the relative polarities, we present in Fig. 4 a sketch of the temporal evolution of the coupling energy in the ideal condition of phase locking ω1 = ω2 for the two cases of identical polarities (φ2 = φ1) and opposite polarities (φ2 = π − φ1). In the case of opposite polarities, when vortices gyrate in opposite directions, the relative alignment of the net magnetizations is always favourable during the motion, so that the mean interaction energy is large and negative. In contrast, when vortices gyrate in identical direction (polarities are identical), the synchronized gyration brings the system in situations when net magnetizations are in a favourable alignment (Wint < 0) but also in a unfavourable alignment (Wint > 0).


Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators.

Locatelli N, Hamadeh A, Abreu Araujo F, Belanovsky AD, Skirdkov PN, Lebrun R, Naletov VV, Zvezdin KA, Muñoz M, Grollier J, Klein O, Cros V, de Loubens G - Sci Rep (2015)

(a) Illustration of the synchronized motion of the two auto-oscillating vortices cores, and of their net in-plane magnetizations (black arrows), for the cases of identical polarities (left) and opposite polarities (right) during one period. The sign of the associated dipolar coupling energy Wint is also given. (b) Predicted evolution of the dipolar coupling energy Wint versus part of oscillation period for identical (blue) and opposite polarities (red). The dotted lines show the average interaction energy in both cases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660301&req=5

f4: (a) Illustration of the synchronized motion of the two auto-oscillating vortices cores, and of their net in-plane magnetizations (black arrows), for the cases of identical polarities (left) and opposite polarities (right) during one period. The sign of the associated dipolar coupling energy Wint is also given. (b) Predicted evolution of the dipolar coupling energy Wint versus part of oscillation period for identical (blue) and opposite polarities (red). The dotted lines show the average interaction energy in both cases.
Mentions: To gain further insight on the relative efficiency of the dipolar action for synchronization depending on the relative polarities, we present in Fig. 4 a sketch of the temporal evolution of the coupling energy in the ideal condition of phase locking ω1 = ω2 for the two cases of identical polarities (φ2 = φ1) and opposite polarities (φ2 = π − φ1). In the case of opposite polarities, when vortices gyrate in opposite directions, the relative alignment of the net magnetizations is always favourable during the motion, so that the mean interaction energy is large and negative. In contrast, when vortices gyrate in identical direction (polarities are identical), the synchronized gyration brings the system in situations when net magnetizations are in a favourable alignment (Wint < 0) but also in a unfavourable alignment (Wint > 0).

Bottom Line: This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures.We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators.Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.

View Article: PubMed Central - PubMed

Affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France.

ABSTRACT
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.

No MeSH data available.