Novel types of magnetic order generated across epitaxial interfaces of 4d and 5d transition metal perovskite oxides

• Applicant: Dr. Ionela Lindfors-Vrejoiu
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 335038432

This research proposal provides the set-up of a new materials platform for generating chiral magnetic domains in poorly conducting or insulating materials. For example all so far known skyrmion phases in thin film samples are currently generated in highly conducting materials. We would like to realize structures in which chiral magnetic order is stabilized at interfaces between oxides that are bad metals or undergo metal-insulator transitions when grown in thin film form. Skyrmions in insulating materials allow different applications than skyrmions in metallic systems, such as skyrmion movement driven by magnon in insulating chiral magnets instead of spin-polarized currents.Major current challenges in the field of magnetic data technology are the improvement of the speed and stability of processing magnetically encoded information, and the development of even more densely-packed data storage concepts, which preferably are also non-dissipative. The majority of nowadays magnetic data storage devices uses ferromagnetic materials where the magnetic order can be described in terms of the strength of the Heisenberg exchange interaction. The exchange interaction in common magnetic materials leads to collinear alignment of lattice spins. However, in materials with broken inversion symmetry and strong spin-orbit coupling, the Dzyaloshinskii-Moriya interaction can stabilize helical magnetic order. The recent discovery of magnetic skyrmions has the potential to open up a completely new vista to reach the higher speed and stability in data recording/processing devices. The revolution made in magnetic data recording technology by Albert Fert and Peter Grünberg discovery of the giant magnetoresistance effect in metallic multilayers stresses out the importance of heterostructures for advances in technology. During the last two decades, epitaxial growth of perovskite oxides with various physical properties has proved itself as a very versatile means to create artificial materials with novel physical properties. In particular we plan to study the effects of epitaxial interfacing and the coupling mechanisms in heterostructures combining 4d and 5d transition-metal oxide layers, such as SrRuO3 and SrIrO3. This heterostructuring is expected to yield non-coplanar spin arrangements in ultrathin ferromagnetic SrRuO3 films and presumably helical order or even skyrmions. The goals are the observation and the study of novel magnetic domain structures in all-oxide heterostructures by Lorentz microscopy and electron holography and magneto-transport measurements.

• DFG Programme: Research Grants
• International Connection: United Kingdom
• Co-Investigators: Professor Dr. Stefan Blügel; Professorin Dr. Regina Dittmann; Professor Dr. Rafal E. Dunin-Borkowski; Dr. Andras Kovacs; Professor Dr. Paul H. M. van Loosdrecht; Professor Dr. Achim Rosch; Professor Dr.-Ing. Rainer Waser
• Cooperation Partner: Professor Dr. Damien McGrouther