Simultaneous transport measurements and highly resolved domain observation of ferromagnetic nanostructures

The electrical conductivity of metals is the fundament of many modern technologies. Besides the electrical properties, magnetic phenomena and their influence on the conductivity of a material are recently in the interest of research and development. In this thesis, the highly resolved observation of ferromagnetic micro- and nanostructures was combined with electrical transport measurements in order to shed light on the principles of magnetoresistive effects such as AMR and BMR. The dependence of the magnetic domain wall width on the geometry of a nanocontact where it is located has been observed with XMCD measurements on T-shaped Permalloy (Ni81Fe19) microstructures. The micromagnetic behavior of ferromagnetic nanocontacts was observed in combination with an in-situ magnetoresistance measurement in the Lorentz TEM, which permits magnetic imaging of ferromagnetic samples with a lateral resolution down to 10 nm or below. Magnetoresistive effects of ferromagnetic structures made of Nickel or Permalloy were correlated with the magnetization distribution in order to clarify the processes that lead to the characteristic magnetoresistive behavior.