Phenomena induced by electric current


Figure. Novel phase locking behaviors of nanomagnetic oscillators driven by spin transfer effect. Top: fractional synchronization (Devilís staircase), bottom: hysteretic parametric synchronization.
Synchronization of nanomagnetic oscillators

Recent developments in nanofabrication techniques and material engineering have enabled new geometries of nanostructures where the Joule heating by electric current becomes relatively unimportant, even when at very large current densities that would vaporize larger structures. Other phenomena then come to the forefront that provide new mechanisms for the manipulation of the nanostructures by electric current. One example is the spin-transfer effect. It enable manipulation of the magnetization in magnetic nanostructures by spin-polarized electric current. In our project, we study the fundamental mechanisms of the interaction between electrical current and the magnetization, and properties of the resulting nonequilibrium magnetization states. The important questions are - Can one describe such states in terms of effective thermodynamic parameters such as temperature, chemical potential etc? - Can the fundamental effects previously observed in other systems, such as Bose-Einstein condensation, be induced by electric current? -Can one engineer a magnetic metamaterial that exhibits a desired response to electric current? From practical viewpoint, these are important questions for designing the future generations of logic devices, sensors, and magnetic nano-oscillators driven by electric current.

Related recent group publications

  • “Control of magnetic fluctuations by spin current; V. Demidov, S. Urazhdin, E. Edwards, M.D. Stiles, R. McMichael and S.O. Demokritov, Phys. Rev. Lett. 107, 107204 (2011)
  • “Fractional synchronization of a spin torque nano-oscillator to a microwave field” S. Urazhdin, P. Tabor, V. Tyberkevych, and A. Slavin, Phys. Rev. Lett. 105, 104101 (2010)
  • “Hysteretic synchronization of nonlinear magnetic nano-oscillators” P. Tabor, V. Tyberkevych, A. Slavin, and S. Urazhdin, Phys. Rev. B 82, 020407(R) (2010), Editor's choice article