Strain-Controlled Magnetic Exchange Coupling in Rigid and Freestanding LaMnO₃/LaNiO₃Multilayers

Exchange bias (EB) generated by interfacial magnetic exchange coupling in magnetic heterostructures has attracted great interest due to its widespread use in spintronic devices. In this work, we fabricate the rigid and freestanding (111)-oriented magnetic multilayers consisting of the LaMnO3 (LMO) antiferromagnetic (AFM) and LaNiO3 (LNO) paramagnetic materials, and study the evolution of magnetic properties. By inserting a water-soluble buffer layer of Sr3Al2O6 (SAO) or Sr1Ca2Al2O6 (SCAO), the EB field of LMO/LNO multilayers is greatly enhanced, and related to buffer layer caused by different strains in multilayers. After the water-soluble sacrificial layer is removed, the interfacial strain between LMO and LNO for the freestanding multilayers transferred on Si substrates can reduce the strength of ferromagnetic (FM)/AFM exchange coupling. Meanwhile, the EB of freestanding multilayers obtained using both the SAO and SCAO layers is nearly identical. Our results provide an effective method to regulate the magnetic properties of oxide heterostructures through strain engineering, and this has potential applications in silicon-based electronics electronics.