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Spin-transfer Torque Induced Magnetization Dynamics

A spin-polarized current entering into a ferromagnetic material exerts a torque on the magnetization by transferring spin angular momentum from the current to the ferromagnet, if the polarization direction differs from the quantization (magnetization) direction in the ferromagnet. This so-called spin-transfer torque gives rise to current-driven magnetization dynamics with unprecedented properties, such as the switching of the magnetization without applying an external field. This current-induced magnetization switching mechanism provides a smart alternative to magnetization switching by induction and is applied in magnetic random access memories (MRAM) for the writing process. Spin-transfer torques can also excite persistent large-angle precessions of the magnetization with frequencies in the GHz range, which are not accessible using magnetic field excitation alone. Persistent current-driven precessions are the basis for the so-called spin-transfer oscillators that are envisaged for applications in communication technology.

Dr. Daniel E. Bürgler


  1. Spin-torque-induced dynamics at fine-split frequencies in nano-oscillators with two stacked vortices
  2. Charging effect reduction in electron beam lithography and observation of single nanopillars on highly insulating substrates
  3. Quenched Slonczewski windmill in spin-torque vortex oscillators
  4. Spin-Transfer Torque Induced Vortex Dynamics in Fe/Ag/Fe Nanopillars
  5. Injection Locking of the Gyrotropic Vortex Motion in a Nanopillar
  6. Magnetization Dynamics in STOs: Vortex State versus Uniform State
  7. Spin-Transfer Induced Dynamic Modes in Single-Crystalline Fe/Ag/Fe Nanopillars
  8. Asymmetric Spin-transfer Torque
  9. Normal and Inverse Current-induced Magnetization Switching
  10. Fabrication Process for Nanopillars