Enhancing the injection locking range of spin torque oscillators through mutual coupling

M. Romera (1) , P. Talatchian (1) , R. Lebrun (1) , K.J. Merazzo (2) , P. Bortolotti (1) , L. Vila (2) , J. Costa (3) , R. Ferreira (3) , P. P. Freitas (3) , M.-C. Cyrille (4, 2) , U. Ebels (2) , V. Cros (1) , J. Grollier (1)

1 Laboratoire Albert Fert (ex-UMPhy Unité mixte de physique CNRS/Thales)
2 SPINTEC - SPINtronique et TEchnologie des Composants
3 INL - International Iberian Nanotechnology Laboratory
4 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

We investigate how the ability of the vortex oscillation mode of a spin-torque nano-oscillator to lock to an external microwave signal is modified when it is coupled to another oscillator. We show experimentally that the mutual electrical coupling can lead to locking range enhancements of a factor 1.64. Furthermore, we analyze the evolution of the locking range as a function of the coupling strength through experiments and numerical simulations. By uncovering the mechanisms at stake in the locking range enhancement, our results will be useful for designing spin-torque nano-oscillator arrays with high sensitivities to external microwave stimuli

Mots clés: Coupled oscillators; Microwave sources; Rotating flows; Materials analysis; Electric currents

Domaines: Physique [physics]

M. Romera, P. Talatchian, R. Lebrun, K.J. Merazzo, P. Bortolotti, et al.. Enhancing the injection locking range of spin torque oscillators through mutual coupling. Applied Physics Letters, 2016, 109, pp.252404 ⟨10.1063/1.4972346⟩. ⟨hal-01614037⟩