Strain–induced robust ferromagnetism and exchange bias effect in epitaxial LaMnO3/SrFeO2.5 bilayer

• Published in: Journal of alloys and compounds Vol. 1036; p. 181931
• Main Authors: Zhang, Jun, Zhao, Ye, Shen, Yufan, Gao, Xiaoli, Ma, Jianchun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.07.2025
• Subjects: Coercivity; Double exchange mechanism; Exchange bias field; Magnetic anisotropy; Double exchange mechanism; Exchange bias field; Magnetic anisotropy; Coercivity
• DOI: 10.1016/j.jallcom.2025.181931
• ISSN: 0925-8388

Exchange bias (EB), commonly observed at the interface between ferromagnetic (FM) and antiferromagnetic (AFM) materials, significantly impacts the performance of magnetic memory devices. Here, we employed A–type AFM LaMnO3 (LMO) and G–type AFM SrFeO2.5 (SFO) native materials as the research subjects, and constructed bilayers with reversed stacking sequences. When SFO was deposited preferentially, the ferromagnetism and EB effect of the SFO/LMO bilayer were relatively weak. Conversely, when LMO was deposited preferentially, the large tensile–strain provided by the SrTiO3 (STO) substrate led to an increased presence of Mn4 + ions within the LMO layer in the LMO/SFO bilayer, in which the double exchange mechanism of the Mn3+–O–Mn4+ ions not only resulted in robust ferromagnetism but also coupled with SFO to generate a significant EB effect. Our research presents a strategy for modulating the magnetic properties and the coupling behavior at the heterogeneous interface via strain engineering, thus broadening the techniques for generating EB. •The antiferromagnetic SrFeO2.5 and antiferromagnetic LaMnO3 targets were used to prepare bilayer.•The tensile strain of the substrate causes more Mn4+ ions to be generated in the LaMnO3 layer.•There is a strong exchange bias between ferromagnetic LaMnO3 induced by tensile strain and antiferromagnetic SrFeO2.5.