Imaging antiferromagnetic antiphase domain boundaries using magnetic Bragg diffraction phase contrast

Abstract

Manipulating magnetic domains is essential for many technological applications. Recent breakthroughs in Antiferromagnetic Spintronics brought up novel concepts for electronic device development. Imaging antiferromagnetic domains is of key importance to this field. Unfortunately, some of the basic domain types, such as antiphase domains, cannot be imaged by conventional techniques. Herein, we present a new domain projection imaging technique based on the localization of domain boundaries by resonant magnetic diffraction of coherent X rays. Contrast arises from reduction of the scattered intensity at the domain boundaries due to destructive interference effects. We demonstrate this approach by imaging antiphase domains in a collinear antiferromagnet Fe2Mo3O8, and observe evidence of domain wall interaction with a structural defect. This technique does not involve any numerical algorithms. It is fast, sensitive, produces large-scale images in a single-exposure measurement, and is applicable to a variety of magnetic domain types.

Seeing is believing: visualization of antiferromagnetic domains

“…One can classify the type of studies in three main categories: (1) scattering experiments with a micro-or nano-focused X-ray beam, in the hard or soft X-ray regime, where it is possible to simultaneously spatially resolve the AFM wave-vector and magnetization density, including chirality of the different domains, and in some cases their depth dependence, 105 (2) scanning X-ray microscopy and X-ray photo emission electron microscopy (PEEM) both using the absorption contrast produced by magnetic linear dichroism to probe the moment direction along the polarization direction of the incident light, and (3) coherent X-ray imaging in Bragg condition, to image certain types of AFM domains. 106 In the hard X-ray regime, and away from atomic resonances, coupling of the photon field to spin and orbital momentum of the electron is intrinsically weak (of the order hν/(mc 2 ), compared to Thomson scattering. Nonetheless, with very bright beams of 3rd and 4th generation synchrotron, it has become possible to study the AFM ordered states of systems even with S = 1/2, 107 as long as the signal is not dominated by charge scattering (ideally when the AFM wave-vector lies inside the Brillouin zone).…”

“…The phase domain patterns can be obtained by the detection of domain boundaries using the destructive interference of the magnetic Bragg signals from the adjacent domains. 106 In principle, the AFM domains can also be imaged by Fourier transform holography utilizing interference of the incident and the diffracted beams, 120 and by several existing coherent diffraction imaging techniques that reconstruct the domain pattern from the observed complex detector images using iterative phase retrieval algorithms. 121 Various related approaches utilizing scanning of a nanoscale-sized coherent X-ray beam across the surface of the sample 121 should also work.…”

Large Magneto-piezoelectric Effect in EuMnBi2 Single Crystal at Low Temperatures

“…2c, red dots correspond to the laser spot of the laser Doppler vibrometer. The diameter of the laser spot is several tens of micrometers, which can be smaller than the size of antiferromagnetic domains [22][23][24] .…”

Band-Mott mixing hybridizes the gap in Fe2Mo3O8

“…The system has a 61 K magnetic ordering transition to a collinear antiferromagnetic state with a concomitant structural distortion [14,[24][25][26][27]. Antiferromagnetic antiphase domain boundaries have been imaged in this state [28]. Fe 2 Mo 3 O 8 also displays a 5 T transition to the ferrimagnetic state with an extremely large magnetoelectric coefficient [14,15].…”