Figure. Directional emission of spin waves by a point contact driven by dc electric current.
emission of spin waves by point contact

Figure. Spin-wave interferometer.
Spin Wave Interference

Electromagnetic waves propagating in magnetic media, called the spin-wsaves, exhibit some very unusual properties. Their spectrum is ansitropic, and this anisotropy is controlled simply by rotating the direction of the magnetization in the medium, changing the wave characterstics such as propagation direction relative to the wavevector, velocity, and relaxation length. Thus, one can contemplate a new class of optical (magnonic) devices, such interferometers, polarizers, frequency multipliers, logic, etc. that utilize magnetic media to attain externally controlled characteristics. In collaboration with the nonlinear dynamics group at the University of Muenster, Germany, we studying the properties of spin-waves and the physical mechanisms that underly the operation of such devices.

Related recent group publications

  • “Spin-torque nano-emitters for magnonic applications; H. Ulrichs, V.E. Demidov, S.O. Demokritov, and S. Urazhdin, Appl. Phys. Lett., in press (2012)
  • “ Resonant frequency multiplication in microscopic magnetic dots; V. Demidov, H. Ulrichs, S. Urazhdin, S.O. Demokritov, V. Bessonov, R. Gieniusz, and A. Maziewski, Appl. Phys. Lett. 99, 012505 (2011)
  • “Control of spin-wave emission in spin-torque nano-oscillators by microwave pumping” V. Demidov, S. Urazhdin, V. Tiberkevich, A. Slavin, and S.O. Demokritov, Phys. Rev B 83, 060406(R) (2011)
  • “Direct observation and mapping of spin waves emitted by spin-torque nano-oscillators” V. Demidov, S. Urazhdin and S.O. Demokritov, Nature Mater. 9, 984 (2010)
  • “Dynamic control of spin-wave phase and wavelength on the microscopic scale” V. Demidov, S. Urazhdin and S.O. Demokritov, Appl. Phys. Lett. 95, 262509 (2009)