On and off Resonant X-ray Diffraction Crytallography on a magnetically taylored manganite superlattice.

Aiming at designing novel magnetic materials, we are coordinating theoretical calculations and
fabrication of heterostructure systems magnetically tailored by strain engineering. Controlled strain
can be applied on magnetic films epitaxially grown on crystalline substrate. We have grown films of
doped manganites that are notoriously sensitive to external fields but are difficult to model because of
the random positions of dopants and their inherent strongly correlated effects. As a start, a realistic
atomic structure is necessary to predict the magnetic properties but ab initio structures have proved to
be difficult to calculate. With this proposal, we aim at determining the crystallographic structure of a
manganite multilayer unit cell, in particular determining as accurately as possible the oxygen positions
that determine the magnetic couplings between Mn atoms. On and off resonant diffraction
methodologies are combined to achieve this challenging thin film crystallography study.