Project Details
Projekt
Electric Control of Skyrmions and Antiskyrmions in Multiferroic Nanostructures and Epitaxial Films
Applicant
Professor Dr. István Kézsmárki
Subject Area
Experimental Condensed Matter Physics
Term
from 2018 to 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 403505061
The detailed knowledge about the behavior and the control of skyrmions in nanostructures and thin films is a prerequisite for their applications as magnetic bits in future memory devices. The emerging field of skyrmionics, aiming at the creation and the manipulation of skyrmions by external stimuli, signals a transition from purely fundamental research towards real technical applications. The corresponding proof-of-principles studies have been focused so far on Bloch-type skyrmions in nanostructures and thin films of chiral cubic compounds as well as on skyrmions emerging at interfaces. In both cases, the manipulation of skyrmions was achieved by electric currents, due to the conducting nature of the host materials. The very recent realization of Néel-type skyrmions by our group and the observation of antiskyrmions by Stuart Parkin and coworkers this year opened new perspectives in skyrmionics.Within this project, we plan to investigate the electric-field control of skyrmions and antiskyrmions in nanostructures and epitaxial films of multiferroic insulators. This approach has several technological advantages: First, the electric-field control requires much lower energy consumption as compared to the electric-current control. Moreover, Néel-type skyrmions and antiskyrmions, present in crystals with axial symmetry, are more robust than Bloch-type skyrmions in terms of thermal stability. In one part of the project, we aim at the realization of the electric-field control of Néel-type skyrmions in nanostructures of lacunar spinels, which we recently established as a novel class of multiferroic compounds. We are going to exploit the voltage-control of the ferroelectric domains together with the strong entanglement between the magnetic and ferroelectric domain walls to study the effect of geometrical constrains on Néel-type skyrmion arrays and to achieve their electric manipulation. As the ultimate goal, we are going to demonstrate the creation of individual Néel-type skyrmions by electric fields. In the other part of the project, taking advantage of the structural polymorphism of lacunar spinels, we aim at the switching between the Néel-type skyrmion and the antiskyrmion lattice states via uniaxial strain and electric field in single crystals and epitaxial films of these compounds. Such skyrmion-antiskyrmion phase transformations are not only of fundamental interest, but represent a technologically important issue, since differences in the internal structures of the two types of objects promote different ways of their external controls.These goals will be reached by combining several experimental methods including dielectric spectroscopy, electron spin resonance spectroscopy, magnetoelectric, magneto-transport and magneto-optical measurements, as well as real- and reciprocal-space imaging techniques (MFM, LTEM, SANS). All of them have been applied successfully for the study of skyrmions by our group or by our collaborators within the SPP.
DFG Programme
Priority Programmes
