Frequency modulation of spin torque oscillator pairs

TL;DR

This paper investigates how frequency modulation affects pairs of spin torque oscillators in synchronized and non-synchronized states, revealing their behavior and interactions, with implications for large array applications.

Contribution

It provides a detailed analysis of current-controlled frequency modulation in STO pairs, highlighting differences between synchronized and non-synchronized states and their modeling.

Findings

Synchronized STO pairs exhibit robust mutual locking under modulation.

Sideband power distribution aligns with a single oscillator model in synchronized state.

Non-synchronized state shows deviations indicating interactions between STOs.

Abstract

The current controlled modulation of nano-contact based spin torque oscillator (STO) pairs is studied in both the synchronized and non-synchronized 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 non-synchronized state, the modulation sidebands are not well described by the model, indicating interactions between the two individual nano-contact STOs. These findings are promising for potential applications requiring the modulation of large synchronized STO arrays.