title: Identification of inversion domains in KTiOPO4 via resonant X-ray diffraction.
abstract: A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO4. Resonant (or 'anomalous') X-ray diffraction spectra collected across the absorption K edge of Ti (4.966 keV) on a single Bragg reflection demonstrate a huge intensity ratio above and below the edge, providing a polar domain contrast of ∼270. This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam. This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics).
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England.
authors.forename: Federica
authors.initials: F
authors.lastname: Fabrizi
authors.affiliation: Department of Physics, University of Warwick, Coventry, CV4 7AL, England.
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Thomas
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England.
authors.forename: Gareth
authors.initials: G
authors.lastname: Nisbet
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Collins
keywords: absolute structure; ferroelectrics; imaging; inversion domains; inversion symmetry; resonant X-ray diffraction; synchrotron radiation