Room-temperature two-dimensional itinerant ferromagnetism in the SrRuO₃-monolayer-based superlattice
Heng-Jui Liu1*, Chao-Yao Yang2, Yi-Ying Chin3, Hong-Ji Lin4, Mao Ye5, Yue-Wen Fang6
1Department of Materials Science and Engineering, National Chung Hsing University, Taichung, Taiwan
2Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
3Department of Physics, National Chung Cheng University, Chiayi, Taiwan
4National Synchrotron Radiation Research Center, Hsinchu, Taiwan
5Department of Physics, Southern University of Science and Technology, Shenzhen, China
6Laboratory for Materials and Structures & Tokyo Tech World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
* Presenter:Heng-Jui Liu,
Two-dimensional intrinsic ferromagnets have caused wide interest due to their great potential to unlock novel physics and fulfill the goal of low-power, fast computing, and ultra-high density spintronic devices. Relying on the recent advances in thin film techniques, creating an artificial quasi-2D oxide monolayer with strong ferromagnetic ground state and requirement of large-area production has become feasible. Particularly, perovskite-based heterostructures have offered an excellent platform to manipulate spin-orbital-charge coupling, unveiling a series of emergent spin-dependent phenomena. In this work, we have fulfilled a robust room-temperature soft ferromagnetism together with a metallic characteristic based on a high quality SrRuO3-monolayer-based superlattice. Further examination on this short-range ferromagnetism has been carried out by synchrotron-related spectroscopy, where charge-transfer-induced antiferromagnetic coupling between partial Ru and Ti ions have been found. Our study not only offers the details of characterization of this oxide-monolayer-based heterostructure, but also a more comprehensive understanding in the origin of 2D ferromagnetism in this system from both experiment and theory.

Keywords: room-temperature 2D ferromagnetism, strontium ruthenate monolayer, oxide heterostructures, spin-polarized 2D electron gas