Multiferroics

Connections between the different aspects of a material are giving rise to new functionalities.


Diagram showing the magnetic order and electric polarisation (P) in copper niobate. See Johnson et al.

Multiferroics can be described as materials in which there are couplings between different types of ordering, including magnetic, charge, and elastic orders. The linkages mean that the properties of these systems are highly susceptible to multiple external perturbations, for example we might access control of the magnetic order by dropping a voltage across the sample, or actuate a strain within the crystal by applying a magnetic field. Clearly abilities like these are ripe for technological application, but first we need to understand why these couplings develop and how to foster them so that we can find a recipe for creating multiferroics with made-to-measure properties. We do this by applying the full range of our experimental capabilities to investigate the ordered phases found within these fascinating materials.

Schematic 3D reciprocal space reconstruction of the Bragg satellite helices observed in ytterbium-iron-oxide The complex synchrotron x-ray scattering patterns are likely due to an exotic type of charge order that can explain the unusual electric properties of this multiferroic material. See Hearmon et al.

Groups working in this field