  Transition metal oxides show fascinating physical properties such as high
temperature superconductivity, ferro- and antiferromagnetism, ferroelectricity
or even multiferroicity. The enormous progress in oxide thin film technology
allows us to integrate these materials with semiconducting, normal conducting,
dielectric or non-linear optical oxides in complex oxide heterostructures,
providing the basis for novel multi-functional materials and various device
applications. Here, we report on the combination of ferromagnetic,
semiconducting, metallic, and dielectric materials properties in thin films and
artificial heterostructures using laser molecular beam epitaxy. We discuss the
fabrication and characterization of oxide-based ferromagnetic tunnel junctions,
transition metal-doped semiconductors, intrinsic multiferroics, and artificial
ferroelectric/ferromagetic heterostructures - the latter allow for the detailed
study of strain effects, forming the basis of spin-mechanics. For
characterization we use X-ray diffraction, SQUID magnetometry, magnetotransport
measurements, and advanced methods of transmission electron microscopy with the
goal to correlate macroscopic physical properties with the microstructure of
the thin films and heterostructures.
