Layered Ferromagnetic Structure Caused by the Proximity Effect and Interlayer Charge Transfer for LaNiO<sub>3</sub>/LaMnO<sub>3</sub> Superlattices.

Wang, Mengqin; Zhu, Tao; Bai, He; Yin, Zhuo; Xu, Hao; Shi, Wenxiao; Li, Zhe; Zheng, Jie et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Magnetic proximity-induced magnetism in paramagnetic LaNiO<sub>3</sub> (LNO) has spurred intensive investigations in the past decade. However, no consensus has been reached so far regarding the magnetic order in LNO layers in relevant heterostructures. This paper reports a layered ferromagnetic structure for the (111)-oriented LNO/LaMnO<sub>3</sub> (LMO) superlattices. It is found that each period of the superlattice consisted of an insulating LNO-interfacial phase (five unit cells in thickness, ∼1.1 nm), a metallic LNO-inner phase, a poorly conductive LMO-interfacial phase (three unit cells in thickness, ∼0.7 nm), and an insulating LMO-inner phase. All four of these phases are ferromagnetic, showing different magnetizations. The Mn-to-Ni interlayer charge transfer is responsible for the emergence of a layered magnetic structure, which may cause magnetic interaction across the LNO/LMO interface and double exchange within the LMO-interfacial layer. This work indicates that the proximity effect is an effective means of manipulating the magnetic state and associated properties of complex oxides.