Novel Oxides

Transition metal oxides are of great potential for technological applications since they show a wide range of extraordinary properties like multiferroic behavior, colossal magnetoresistance, and high-Tc superconductivity. The physics of these systems is governed by an intricate interplay of competing interactions among the charge, spin, and orbital degrees of freedom which may result in coexistence or competition of various types of ordered ground states. In order to map the hierarchy of these interactions the combined use of a broad range of experimental techniques is required. HZB houses a wide choice of x-ray and neutron based techniques that are ideally suited for the study of structural, electronic, and magnetic properties of materials. On the firm ground of state-of-the-art sample preparation and characterization we carry out neutron scattering, advanced photon spectroscopy, and resonant x-ray scattering experiments in extreme sample environments which provide combinations of very low temperatures, extremely high magnetic fields, high pressures and other external stimuli. Understanding the response of the investigated materials to variation of any external parameter is the great challenge in the study of multifunctional oxides.

In the following we present a few examples of research carried out within the last few years.

For a full list of publications of our research group klick here.

Hexagonal single crystal of SrCo6O11, with a sample diameter of approximately 0,2 millimetres.

These samples with precise proportions of nickel and copper were produced via an improved preparation procedure. Photo: M. Tovar/HZB

Helical magnetic structure of Sr3Fe2O7 projected onto the ac plane. © APS

Spatial map of the circular XRMS dichroism measured at (0 τMn 0) at the Mn L edge of a TbMnO3 film of 100 nm. The sample was cooled with the x-ray beam at the “burn point” position (green ellipse approximates beam size) and measured at 11 K. The arrows indicate the electric-polarization direction associated with the respective cycloidal domain. © APS

The d-orbital diagram of the valence states of Sr2FeOsO6 in the AF1 and AF2 phases as calculated from the band structures. © APS