Abstract
The current induced manipulation of chiral spin textures is of great interest for both fundamental research and technological applications1–3. Of particular interest are magnetic non-volatile memories formed from synthetic antiferromagnetic racetracks in which chiral composite domain walls (DWs), that act as data bits, can be efficiently moved by current4. However, overcoming the trade-off between energy efficiency, namely a low threshold current density to move the domain walls, and high thermal stability, remains a major challenge for the development of integrated chips with high reliability and low power consumption. Here we show that chiral DWs5–7 in a synthetic antiferromagnet-ferromagnet lateral junction, formed by local plasma oxidation, are highly stable against large magnetic fields whilst the DWs can be efficiently moved across the junction by current. Our approach takes advantage of the locality of current-driven torque on the small volume of a chiral DW and the globality of field-torque in the energy landscape, thereby leading to fundamentally distinct energy barriers for motion and stability. We find that the threshold current can be further decreased by tilting the junction across the racetrack while not affecting the high DW stability. Furthermore, we demonstrate that chiral DWs can be robustly confined within a ferromagnet region sandwiched on both their sides by synthetic antiferromagnets and yet can be readily injected into these regions by current. Our findings break the aforementioned trade-off between efficiency and stability, allowing for diverse and versatile DW-based memory, and logic, and beyond.
Local and global energy barriers for chiral domain walls in synthetic antiferromagnet-ferromagnet lateral junctions
