% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@BOOK{Sluka:890540,
      author       = {Sluka, Volker},
      title        = {{S}pin-{T}ransfer {T}orque {I}nduced {D}ynamics of
                      {M}agnetic {V}ortices in {N}anopillars},
      volume       = {23},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2021-01022},
      isbn         = {978-3-89336-717-7},
      series       = {Schriften des Forschungszentrums Jülich. Reihe
                      Schlüsseltechnologien / key technologies},
      pages        = {121 .},
      year         = {2011},
      abstract     = {The subject of this work are lithographically defined
                      cylindrical nanopillars containing a stack of two Iron disks
                      separated by a nonmagnetic spacer. The dimensions of the
                      ferromagnetic disks are chosen such that at low magnetic
                      fields, the so-called magnetic vortex is stabilized. In zero
                      field, the magnetization of these objects is basically
                      parallel to the disk plane and circulates the disk center.
                      In doing so, the build-up of large in-plane stray fields is
                      avoided. At the center of this distribution however,
                      exchange forces turn the magnetization out of the disk
                      plane, resulting in the formation of what is referred to as
                      the vortex core. Magnetic vortices have attracted much
                      attention in recent years. This interest is in large parts
                      due to the highly interesting dynamic properties of these
                      structures. In this work the static and dynamic properties
                      of magnetic vortices and their behaviorunder the influence
                      of spin-transfer torque are investigated. This is achieved
                      by measuring the static and time dependent magnetoresistance
                      under the influence of external magnetic fields. The samples
                      allow the formation of a large variety of states. First, the
                      focus is set on configurations, where one disk is in a
                      vortex state while the other one is homogeneously
                      magnetized. It is shown that spin-transfer torque excites
                      the vortex gyrotropic mode in this configuration. The
                      dependence of the mode frequency on the magnetic field is
                      analyzed. The measurements show that as the vortex center of
                      gyration shifts through the disk under the action of the
                      magnetic field, the effective potential in which it is
                      moving undergoes a change in shape. This shape change is
                      reflected in a V-shaped field dependence of the gyration
                      frequency. Analytical calculations are performed to
                      investigate the effect of the asymmetry of the spin-transfer
                      torque efficiency function on the vortex dynamics. It is
                      shown that by means of asymmetry, spin-transfer torque can
                      transfer energy to a gyrating vortex even if the
                      spin-polarization of the current is perfectly homogeneous.
                      Subsequently so-called double vortex configurations are
                      considered. These configurations involve states where each
                      of the disks is in a vortex state. Methods for preparing
                      such states are developed and the spin-transfer torque
                      induced dynamics of these configurations is investigated.
                      Rich dynamics is observed, and differences in mode
                      frequencies can be identified as being caused by different
                      combinations ofvortex core polarities. The experiments show
                      that double vortex systems are nonlinear oscillators which
                      show the property of phase locking to an external periodic
                      signal.},
      cin          = {PRE-2000 ; Retrocat / PGI-6},
      cid          = {I:(DE-Juel1)PRE2000-20140101 / I:(DE-Juel1)PGI-6-20110106},
      pnm          = {899 - ohne Topic (POF3-899)},
      pid          = {G:(DE-HGF)POF3-899},
      typ          = {PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/890540},
}