High-resolution hard x-ray magnetic imaging with dichroic ptychography

(a) The dichroic ptychography setup. A diamond phase plate converts linearly polarized light into CL or CR light, which is then focused close to the sample plane. A piezoelectric stage is used to scan the sample across the beam. (b) The absorption part of reconstructed images taken with CL and CR polarized light at the Gd L3 edge with a photon energy of 7.2445 keV, which contain both electron density and magnetic contributions. The difference of these images removes the electron density contrast of Pt refe…
(a) The dichroic ptychography setup. A diamond phase plate converts linearly polarized light into CL or CR light, which is then focused close to the sample plane. A piezoelectric stage is used to scan the sample across the beam. (b) The absorption part of reconstructed images taken with CL and CR polarized light at the Gd L3 edge with a photon energy of 7.2445 keV, which contain both electron density and magnetic contributions. The difference of these images removes the electron density contrast of Pt reference structures on the sample to give a purely magnetic image, i.e., with XMCD contrast. Scale bars represent 1μm.

Abstract:

Imaging the magnetic structure of a material is essential to understanding the influence of the physical and chemical microstructure on its magnetic properties. Magnetic imaging techniques, however, have been unable to probe three-dimensional micrometer-size systems with nanoscale resolution. Here we present the imaging of the magnetic domain configuration of a micrometer-thick FeGd multilayer with hard x-ray dichroic ptychography at energies spanning both the Gd L3 edge and the Fe K edge, providing a high spatial resolution spectroscopic analysis of the complex x-ray magnetic circular dichroism. With a spatial resolution reaching 45nm, this advance in hard x-ray magnetic imaging is a first step towards the investigation of buried magnetic structures and extended three-dimensional magnetic systems at the nanoscale.

Facility: SLS; LMX, Mesoscopic Systems

Reference: C. Donnelly et al, Phys. Rev. B 94, 064421 (2016)

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