Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 42: Focus Session: Curvilinear magnetism

MA 42.3: Hauptvortrag

Donnerstag, 4. April 2019, 10:30–11:00, H38

Chiral magnetoresistance in curved and noncurved geometries — •Pietro Gambardella — Department of Materials, ETH Zurich, Switzerland

Magnetoresistive phenomena occupy a prominent place in current developments of spintronics and spin-orbitronics. This talk will focus on the emergence of chiral electron transport in magnetic conductors due to geometrical effects and spin-orbit coupling. As a first system of interest, we will discuss CoNi microhelices fabricated by electrodeposition. The magnetoresistance of such structures presents a specific angular and field dependence as well as a chiral unidirectional component, which set it apart from the magnetoresistance of thin films and tubular structures. As a second example, we will discuss nanometer-thick layered conductors lacking inversion symmetry. In these systems, charge-spin conversion phenomena due to the spin Hall and Rashba-Edelstein effects also result in a chiral unidirectional magnetoresistance, which scales with the current and changes sign for either current or magnetization reversal. We will describe the different mechanisms that compete to determine the unidirectional resistance in helical and layered conductors, as well as their current, field, and material dependence. These results provide an overview of the magnetoresistance in chiral conductors as well as practical insight on how to design structures that display nonreciprocal electron transport.