Ptychographic nanoscale imaging of the magnetoelectric coupling in freestanding BiFeO${}_3$

Abstract

Understanding the magnetic and ferroelectric ordering of magnetoelectric multiferroic materials at the nanoscale necessitates a versatile imaging method with high spatial resolution. Here, soft X-ray ptychography is employed to simultaneously image the ferroelectric and antiferromagnetic domains in an 80 nm thin freestanding film of the room-temperature multiferroic BiFeO${}_3$ (BFO). The antiferromagnetic spin cycloid of period 64 nm is resolved by reconstructing the corresponding resonant elastic X-ray scattering in real space and visualized together with mosaic-like ferroelectric domains in a linear dichroic contrast image at the Fe L${}_3$ edge. The measurements reveal a near perfect coupling between the antiferromagnetic and ferroelectric ordering by which the propagation direction of the spin cycloid is locked orthogonally to the ferroelectric polarization. In addition, the study evinces both a preference for in-plane propagation of the spin cycloid and changes of the ferroelectric polarization by 71° between multiferroic domains in the epitaxial strain-free, freestanding BFO film. The results provide a direct visualization of the strong magnetoelectric coupling in BFO and of its fine multiferroic domain structure, emphasizing the potential of ptychographic imaging for the study of multiferroics and non-collinear magnetic materials with soft X-rays.

Supporting information available with published version: https://doi.org/10.1002/adma.202311157

References in corpus (5)

• Real-space imaging of non-collinear antiferromagnetic order with a single spin magnetometer
• X-ray linear dichroic ptychography
• Imaging ferroelectric domains with a single-spin scanning quantum sensor
• Development of LGAD sensors with a thin entrance window for soft X-ray detection
• Three-dimensional Resonant Magnetization Dynamics Unraveled by Time-Resolved Soft X-ray Laminography

Cited by in corpus (6)

• Imaging ferroelectric domains with soft X-ray ptychography at the oxygen K-edge
• Nanoscale Domain Wall Dynamics in Micromagnetic Structures with Weak Perpendicular Anisotropy
• Single-photon counting pixel detector for soft X-rays
• Soft x-ray ptychography with SOPHIE: Guide and instrumentation
• Revealing domain wall stability during ultrafast demagnetization
• Supersampled scanning transmission X-ray microscopy for high-resolution vibration-independent time-resolved imaging