| 1. |
- Muduli Kishor, Pranaba, 1978, et al.
(författare)
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Spin Torque Oscillators and RF Currents—Modulation, Locking, and Ringing
- 2011
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Ingår i: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 125:1
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Tidskriftsartikel (refereegranskat)abstract
- We study the interaction between a nano-contact spin torque oscillator (STO) and injected radio-frequency and microwave currents. Modulation of the STO signal is observed over a wide frequency range from 100 MHz to 3.2 GHz. The modulation sidebands agree well with macrospin simulations. When the injected microwave frequency approaches that of the STO, we observe injection locking, frequency pulling/pushing, and intermodulation peaks. While the intermodulation peaks are reasonably well reproduced by macrospin simulations, they do not follow the Adler's model. We argue that this discrepancy is due to intrinsic ringing effects stemming from the internal dynamics of the STO.
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| 2. |
- Muduli, Pranaba, et al.
(författare)
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Modulation of single and double spin torque oscillators
- 2011
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Ingår i: AIP Conf. Proc.. - : AIP. ; 1347
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Tidskriftsartikel (refereegranskat)abstract
- We discuss modulation of metallic spin torque oscillators (STOs) based on single and double nano-contacts. The modulation behavior of both types of devices is characterized by equally spaced multiple sidebands, which can be ascribed mostly to a frequency modulation phenomenon. However, quantitative examination reveals that amplitude modulation is also present in both types of devices. We also show the feasibility of modulating the synchronized state of a double nano-contact STO. The synchronized state can be treated as a single oscillator, which is a very promising feature for future applications of STO arrays.
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| 3. |
- Pogoryelov, Yevgen, 1975, et al.
(författare)
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Frequency modulation of spin torque oscillator pairs
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 98:19
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Tidskriftsartikel (refereegranskat)abstract
- The current controlled modulation of nanocontact based spin torque oscillator (STO) pairs is studied in both the synchronized and nonsynchronized states. The synchronized state shows a well behaved modulation and demonstrates robust mutual locking even under strong modulation. The power distribution of the modulation sidebands can be quantitatively described by assuming a single oscillator model. However, in the nonsynchronized state, the modulation sidebands are not well described by the model, indicating interactions between the two individual nanocontact STOs. These findings are promising for potential applications requiring the modulation of large synchronized STO arrays.
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| 4. |
- Pogoryelov, Yevgen, 1975, et al.
(författare)
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Spin-torque oscillator linewidth narrowing under current modulation
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 98:19
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Tidskriftsartikel (refereegranskat)abstract
- We study the behavior of the linewidth of a nanocontact based spin torque oscillator (STO) under application of a radio frequency (100 MHz) modulating current. We achieve a significant (up to 85%) reduction in the STO linewidth when it is modulated across a region of high nonlinearity. The mechanism responsible for the linewidth reduction is the nonlinear frequency shift under the influence of current modulation, which reduces the nonlinear amplification of the linewidth. The reduction in the linewidth during modulation can be quantitatively calculated from the free-running behavior of the STO.
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