Designed Magnetic Texture for Spin Transport in a Multiferroic Oxide

Antiferromagnetic-based spintronics are growing in popularity for potential applications in next-generation computational technologies due to their speeds and robustness to external fields. A key challenge in this area, however, is the control of antiferromagnetic order on the nanometer scales applicable to solid-state technologies. Bismuth ferrite (BiFeO₃) is a multiferroic material that exhibits both ferroelectric and antiferromagnetic properties at room temperature, making it a unique candidate in the development of electrically controllable magnetic devices. In BiFeO₃, the magnetic moments are arranged into a long-range spin cycloid, resulting in a unique set of magnetic properties that are intimately tied to the ferroelectric order. To date, however, understanding of this coupling between magnetism and ferroelectricity has generally relied on average, mesoscale measurements to infer the magnetic structure and behavior.<br/><br/>Using high-resolution nitrogen vacancy (NV) diamond-based scanning probe magnetometry, we show that this spin cycloid can be deterministically controlled with an electric field. The underlying energy landscape of the spin texture is shaped by both the ferroelectric degree of freedom and strain-induced anisotropy, where electric fields drive magnetoelectric switching in predictable ways that can be engineered. Through precise control of the crystal structure using thin film techniques, the magnetic structure of BiFeO₃ can be tuned to control magnon transport in the material, opening the door for efficient, electrically controllable magnonic devices.