Charge-Transfer-Induced Interfacial Ferromagnetism in Ferromagnet-Free Oxide Heterostructures

Jie Zheng, Wenxiao Shi, Zhe Li, Jing Zhang*, Chao Yao Yang, Zhaozhao Zhu, Mengqin Wang, Jine Zhang, Furong Han, Hui Zhang, Yunzhong Chen, Fengxia Hu, Baogen Shen, Yuansha Chen*, Jirong Sun*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Due to the strong interlayer coupling between multiple degrees of freedom, oxide heterostructures have demonstrated exotic properties that are not shown by their bulk counterparts. One of the most interesting properties is ferromagnetism at the interface formed between “nonferromagnetic” compounds. Here we report on the interfacial ferromagnetic phase induced in the superlattices consisting of the two paramagnetic oxides CaRuO3 (CRO) and LaNiO3 (LNO). By varying the sublayer thickness in the superlattice period, we demonstrate that the ferromagnetic order has been established in both CaRuO3 and LaNiO3 sublayers, exhibiting an identical Curie temperature of ∼75 K. The X-ray absorption spectra suggest a strong charge transfer from Ru to Ni at the interface, triggering superexchange interactions between Ru/Ni ions and giving rise to the emergent ferromagnetic phase. Moreover, the X-ray linear dichroism spectra reveal the preferential occupancy of the d3z2-r2 orbital for the Ru ions and the dx2-y2 orbital for the Ni ions in the heterostructure. This leads to different magnetic anisotropy of the superlattices when they are dominated by CRO or LNO sublayers. This work clearly demonstrates a charge-transfer-induced interfacial ferromagnetic phase in the whole ferromagnet-free oxide heterostructures, offering a feasible way to tailor oxide materials for desired functionalities.

Original languageEnglish
Pages (from-to)9232-9241
Number of pages10
JournalACS Nano
Volume18
Issue number12
DOIs
StatePublished - 26 Mar 2024

Keywords

  • CaRuO
  • charge transfer
  • interfacial ferromagnetism
  • LaNiO
  • orbital reconstruction

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