![]() ![]() From a single-shot geometry, we extract a two-dimensional image of the sizes and relative positions of the first domains formed in the antiferromagnetic transition of a -oriented PrNiO 3 thin film. Here, we continue on a related path by demonstrating that a special case of the Bragg coherent diffractive imaging (BCDI) ( 19) technique can be applied to study the mesoscopic features of a two-dimensional antiferromagnetic texture, using resonant x-rays to achieve sensitivity to antiferromagnetic Bragg scattering. This result represents an important step forward for coherent x-ray–based imaging of antiferromagnetic domain structures, although it remains to be seen with what generality XBPM can be applied. Recently, resonant x-ray Bragg diffraction phase contrast microscopy (XBPM) ( 18) was used to resolve images of antiphase domain boundaries, directly visible on the tails of the specular (001) magnetic Bragg reflection in the collinear antiferromagnet Fe 2Mo 3O 8. To image the dynamics and collective excitations associated with antiferromagnetic textures, it would be desirable to identify a nonscanning imaging modality with direct sensitivity to antiferromagnetism. Some notable exceptions exist, for example, stroboscopic time-resolved STXM ( 16) and stroboscopic resonant magnetic dichroic ptychography ( 17), which have been used to capture spatially resolved magnetization dynamics. While scanning techniques are numerous and produce relatively simple-to-interpret images, they are inherently slow and therefore often cannot be extended to capture dynamically evolving systems. These include both resonant and nonresonant scanning magnetic diffraction ( 7, 8), spin-polarized scanning tunneling microscopy ( 9), magneto-optical Kerr effect microscopy, magnetic force microscopy ( 10), spatially resolved second harmonic generation ( 11), magnetic linear dichroic scanning transmission x-ray microscopy (STXM) ( 12), and others ( 13– 15). Scanning techniques to study antiferromagnetism are the most common and have been implemented for both direct and indirect probes. While certain anomalous features in the nano-infrared response probed by SNOM were interpreted as arising from the presence of antiferromagnetic antiphase domain boundaries, the first direct identification of the antiferromagnetic domain morphology in this material was reported using resonant magnetic Bragg scattering applied in a scanning mode ( 7).Īntiferromagnetic imaging techniques can be further broken down into scanning-type and single-shot (single-geometry) experiments. In NdNiO 3, both linear dichroic x-ray photoemission electron microscopy and scanning near-field optical microscopy (SNOM) have been successful in imaging the metal-insulator transition ( 5, 6) but are less sensitive to the noncollinear antiferromagnetism of the Ni spins. For example, the rare-earth nickelates PrNiO 3 and NdNiO 3 exhibit a propensity toward a correlation-driven insulating ground state, characterized by a bond order and a coupled noncollinear antiferromagnetic order with twice the periodicity. The need for a direct probe of antiferromagnetism becomes particularly acute in materials with technologically relevant couplings between lattice, spin, charge, and orbital degrees of freedom. While some of these techniques probe antiferromagnetism directly, for example, by accessing an antiferromagnetic Bragg condition in a diffraction experiment, the wide majority probe antiferromagnetism indirectly, such as optical birefringence ( 1, 2), or linear dichroic x-ray microscopies ( 3, 4), which are sensitive to the spin-orbit coupling–mediated effect of antiferromagnetism on the surrounding electronic and structural environment. Over the past decades, a variety of experimental techniques have emerged, making it possible to image antiferromagnetic textures over mesoscopic length scales. We demonstrate that it is possible to extract the arrangements and sizes of these domains from single diffraction patterns and show that the approach could be extended to a time-structured light source to study the motion of dilute domains or the motion of topological defects in an antiferromagnetic spin texture. We study the onset of the antiferromagnet transition in PrNiO 3, focusing on a temperature regime in which the antiferromagnetic domains are dilute in the beam spot and the coherent diffraction pattern modulating the antiferromagnetic peak is greatly simplified. In this work, we demonstrate that Bragg coherent diffractive imaging can be extended to study the mesoscopic texture of an antiferromagnetic order parameter using resonant magnetic x-ray scattering. A fundamental step is identifying tools to probe the mesoscopic texture of an antiferromagnetic order parameter. The detection and manipulation of antiferromagnetic domains and topological antiferromagnetic textures are of central interest to solid-state physics. ![]()
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