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B3: Magneto-electro-optical interactions and their dynamics in oxide heterostructures

The main objective of the project is the demonstration of a remanently electrical switchable optical waveguide. In that, the switching state of a ferroelectric or multiferroic material, which is deposited on top of the dielectric or semiconducting micro-dimensional waveguide, shall be used as an information unit (bit). Switching changes the electric or magnetic fields within the waveguide mediated by the interface. The properties of optical modes changed suchely can be easily detected and thus the switching state can be read out. Such interfaces between optics and electronics are relevant e.g. for optical circuits or optical interconnects in multicore processors.

Towards the realization of such structures, the electro- and magneto-optical properties of ferroelectric, magnetic and multiferroic materials and heterostructures shall be investigated. Hence, also new fundamental physical understanding is expected, for example regarding the correlation of properties of electronic transitions, which can be observed in the materials dielectric function, with the electronic orbitals related to magnetic or ferroelectric order. For that purpose, spectroscopic ellipsometry, magneto-optical spectroscopy and Raman scattering shall be applied, also depending on temperature in order to observe phase transitions.

Of particular interest are the dynamic properties of the dielectric function. Here it shall be investigated how the dynamics of ferroelectric or multiferroic switching operations influence the time scales of the effects which can be observed in the dielectric function. Time scales ranging from fs (pump-robe spectroscopy) via ps to ms (time-resolved ellipsometry) are of interest.

As “ferroic” materials, mainly the material classes spinels and hexagonal manganates, which have also been investigated in the last funding periods, but also BaTiO₃/BiFeO₃-composite-/multilayer-multiferroica as well as further innovative materials shall be used.

Principal Investigators

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