Thin Films & Nanostructures


Eu intermetallics

Valence Transition in Eu-Intermetallics

In some Europium (EU) intermetallic compounds a temperature- and/or pressure-driven valence transition occurs which renders the Eu valence from 2+ to 3+, thus changing its magnetic moment from 7 μB to 0. This valence transition is accompanied by a pronounced reduction of the unit cell volume. In our research, which is part of the Collaborative Research Center (CRC TRR288) Elasto-Q-Mat, we focus on epitaxial thin films of EuPd2Si2 and EuPd3 grown by MBE and the study of strong coupling effects between electronic fluctuations and the lattice degrees of freedom, e.g. by way of surface acoustic wave (SAW) attenuation measurements.

MnSi phase diagram

Thin Film Helimagnets

Helical magnets are highly fascinating as model systems for complex magnetic ordering which can exhibit such properties as multiferroicity and the appearance of stable magnetic skyrmions, i.e. magnetic vortex structures of non-trivial topology. The interplay of the various energy scales often leads to magnetic ordering, exhibiting a periodicity that is incommensurate with the lattice. MnSi, a non-centrosymmetric itinerant magnet, is a prominent example showing incommensurate helical order and a magnetic phase diagram that can be strongly modified by thin film specific effects, such as clamping and strain. We grow epitaxial MnSi thin films by MBE and are particularly interested in the interplay of the magnetic phases of MnSi and Abrikosov vortex lattices in MnSi/superconductor double-layer structures.