Our recent study on the noise-induced synchronization of stochastic magnetic oscillators, based on magnetic tunnel junctions in the superparamagnetic state, has just appeared in Physical Review Applied.
In the superparamagnetic state, the free layer magnetization of the magnetic tunnel junction switches randomly between the parallel and antiparallel states, leading to telegraph noise in the electrical signal through the tunneling magnetoresistance effect. We demonstrate experimentally that this switching can be phase-locked to an external rf current, for current densities below 3 MA/cm2, with locking frequencies below the natural mean frequency of the stochastic oscillator. Such injection locking may have potential applications as low-power spin-torque nano-oscillator arrays.
Acknowledgements: The authors acknowledge financial support from the FET-OPEN Bambi project No. 618024. A. A. acknowledges financial support from the Brazilian Agency National Council for Scientific and Technological Development (CNPq, Project No. 245555/2012-9), and A. M. from the Ile-de-France regional government through the DIM nano-K program.