Double-Exchange Bias Modulation under Horizontal and Perpendicular Field Directions by 3D Nanocomposite Design

Exchange bias (EB) presents the interfacial coupling between ferromagnetic (FM) and antiferromagnetic (AFM) phases, which could be applied for high-density data storage and magnetic recording. In thin films, the EB effect could be realized in either a FM/AFM multilayer structure or a FM/AFM vertically aligned nanocomposite (VAN) form, which allows the interfacial coupling tuning along the horizontal or perpendicular directions, respectively. Here, to combine the schemes of multilayer and VAN structures, a new 3D nanocomposite has been designed, which is La_0.7Sr_0.3MnO₃ (LSMO)/NiO VAN layers with inserted LSMO or NiO layers. Such a 3D nanocomposite structure provides a great platform to tailor the EB effect along both horizontal and perpendicular directions. Specifically, the sample with a NiO interlayer exhibits the highest EB field (H_EB) of 350 Oe and 475 Oe under in-plane and out-of-plane field, respectively. Furthermore, the H_EB value and Curie temperature (T_c) can be tuned by different 3D nanostructures. This work demonstrates the double EB modulation with the designed 3D nanostructures as a new route toward advanced magnetic data storage and spintronic devices.