Hard X-ray polarizer to enable simultaneous three-dimensional nanoscale imaging of magnetic structure and lattice strain

Abstract

Recent progress in the development of dichroic Bragg coherent diffractive imaging, a new technique for simultaneous three-dimensional imaging of strain and magnetization at the nanoscale, is reported. This progress includes the installation of a diamond X-ray phase retarder at beamline 34-ID-C of the Advanced Photon Source. The performance of the phase retarder for tuning X-ray polarization is demonstrated with temperature-dependent X-ray magnetic circular dichroism measurements on a gadolinium foil in transmission and on a Gd 5 Si 2 Ge 2 crystal in diffraction geometry with a partially coherent, focused X-ray beam. Feasibility tests for dichroic Bragg coherent diffractive imaging are presented. These tests include (1) using conventional Bragg coherent diffractive imaging to determine whether the phase retarder introduces aberrations using a nonmagnetic gold nanocrystal as a control sample, and (2) collecting coherent diffraction patterns of a magnetic Gd 5 Si 2 Ge 2 nanocrystal with left-and right-circularly polarized X-rays. Future applications of dichroic Bragg coherent diffractive imaging for the correlation of strain and lattice defects with magnetic ordering and inhomogeneities are considered.

Understanding nanoscale structural distortions in Pb(Zr0.2Ti0.8)O3 by utilizing X-ray nanodiffraction and clustering algorithm analysis

“…In the last few decades, hard X-ray microscopy has emerged as a novel method to characterize nanoscale heterogeneities in functional oxides (Holt et al, 2013;Logan et al, 2006;Hruszkewycz et al, 2013Hruszkewycz et al, , 2014Winarski et al, 2012). Specifically, hard X-ray microscopy techniques have shown certain advantages over complementary electron microscopy techniques for functional oxides, as no alterations of local boundary conditions occur during sample preparation or measurement due to comparatively weak sample-beam interaction.…”

Polarization control of an x-ray free electron laser oscillator

“…In hard X-ray region, circularly polarized laser makes it possible to observe inner 3-dimensional magnetic structure with a large dichroic effect for 3d transition metals by employing bulk-sensitive X-ray magnetic circular dichroism measurement [18][19][20]. Further, by using the combination of hard X-ray magnetic circular dichroism spectroscopy and Bragg coherent diffractive imaging, one may gain the ability to study magnetic structure and strain mapping in a single X-ray pulse [21,22]. Purely 45 • linearly polarized hard Xray is also in a considerable demand in quantum-electrodynamics (QED) experiments on a extreme light station [23].…”