Emergent and robust ferromagnetic-insulating state in highly strained ferroelastic LaCoO3 thin films

Dong Li, Hongguang Wang*, Kaifeng Li, Bonan Zhu*, Kai Jiang*, Dirk Backes, Larissa S.I. Veiga, Jueli Shi, Pinku Roy, Ming Xiao, Aiping Chen, Quanxi Jia, Tien Lin Lee, Sarnjeet S. Dhesi, David O. Scanlon, Judith L. MacManus-Driscoll, Peter A. van Aken, Kelvin H.L. Zhang*, Weiwei Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Transition metal oxides are promising candidates for the next generation of spintronic devices due to their fascinating properties that can be effectively engineered by strain, defects, and microstructure. An excellent example can be found in ferroelastic LaCoO3 with paramagnetism in bulk. In contrast, unexpected ferromagnetism is observed in tensile-strained LaCoO3 films, however, its origin remains controversial. Here we simultaneously reveal the formation of ordered oxygen vacancies and previously unreported long-range suppression of CoO6 octahedral rotations throughout LaCoO3 films. Supported by density functional theory calculations, we find that the strong modification of Co 3d-O 2p hybridization associated with the increase of both Co-O-Co bond angle and Co-O bond length weakens the crystal-field splitting and facilitates an ordered high-spin state of Co ions, inducing an emergent ferromagnetic-insulating state. Our work provides unique insights into underlying mechanisms driving the ferromagnetic-insulating state in tensile-strained ferroelastic LaCoO3 films while suggesting potential applications toward low-power spintronic devices.

Original languageEnglish
Article number3638
JournalNature Communications
Volume14
Issue number1
DOIs
Publication statusPublished - Dec 2023
Externally publishedYes

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