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@PHDTHESIS{Gospodaric:865992,
      author       = {Gospodaric, Pika -> Gospodaric, Pika (FZJ:
                      pi.gospodaric@fz-juelich.de / PGI-6)},
      title        = {{C}urrent-induced magnetization switching in a model
                      epitaxial {F}e/{A}u bilayer},
      volume       = {202},
      school       = {Universität Duisburg},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2019-05253},
      isbn         = {978-3-95806-423-2},
      series       = {Schriften des Forschungszentrums Jülich. Reihe
                      Schlüsseltechnologien / Key Technologies},
      pages        = {vi, 120, XXXVIII S.},
      year         = {2019},
      note         = {Universität Duisburg, 2019},
      abstract     = {In electronics, the application of novel spintronic
                      three-terminal memory devices is proposed to facilitate
                      further improvements of the performance of electronic
                      components. A promising write-mechanism in a spintronic
                      memory is based on the purely electricalswitching of the
                      magnetization by $\textit{spin-orbit torque}$ (SOT) that can
                      occur, for example, at the interface of heavy metal
                      (HM)/ferromagnetic metal (FM) bilayers. This thesis presents
                      a study of the epitaxial model HM/FM system Au(4 nm)/Fe(1-
                      1.5 nm)/MgO(001) using magneto-transport measurements and
                      Kerr microscopy. The Au/Fe bilayers were
                      photolithographically patterned into Hall bars in order to
                      study their magnetic and magneto-transport properties. The
                      Au/Fe bilayer Hall bars on MgO(001) substrate exhibit a
                      strong in-plane easy magnetization axis and a cubic magnetic
                      anisotropy in the film plane dominated by the
                      magneto-crystalline term of the Fe(001) layer. In the chosen
                      geometry of the samples the easy magnetization directions
                      coincide with the extrema of the transversal voltage induced
                      by the planar Hall effect (PHE). Therefore, a switching of
                      the magnetization from one easy direction to another can be
                      detected by measuring the PHE-voltage. Furthermore, Kerr
                      microscopy revealed the formation of stripe-shaped magnetic
                      domains separated by 90$^\circ$ domain walls aligned
                      perpendicular to the Hall bar. A combined measurement of
                      PHE-voltage and acquisition of Kerr images has shown that
                      the measured PHE-voltage is most considerably affected by
                      the domain configuration within the central area of the Hall
                      cross. Based on this findings, the influence of electrical
                      currents on the magnetization in the Fe(001) layer was
                      investigated via measurements of the PHE combined with Kerr
                      microscopy. At room temperature, a current density beyond
                      10$^{7}$ A/cm$^{2}$ induces an Oersted field, which in the
                      Fe(001) layer points in-plane in the direction perpendicular
                      to the long axis of the Hall bar and can exceed the coercive
                      field B$_{c}$=0.65$\pm$0.05 mT for the 90$^\circ$ switch of
                      the magnetization. Moreover, a current density beyond
                      1.4$\cdot$10$^{7}$ A/cm$^{2}$ with an alternating polarity
                      can be employed for reproducible electrical switching of the
                      magnetization in the Au/Fe/MgO(001) Hall bars between
                      multiple stable states. Kerr microscopy confirmed that a
                      variation of the applied current density changes the domain
                      structure at the Hall bar cross. The change of the domain
                      structure scales with the applied current density and can be
                      read-out as a change in the PHE-voltage. The PHE
                      measurements at T<50 K indicate a presence of an additional
                      current-induced field up to 2.5 mT in the direction normal
                      to the film surface.},
      cin          = {PGI-6},
      cid          = {I:(DE-Juel1)PGI-6-20110106},
      pnm          = {522 - Controlling Spin-Based Phenomena (POF3-522)},
      pid          = {G:(DE-HGF)POF3-522},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/865992},
}