Room-temperature two-dimensional itinerant ferromagnetism in the SrRuO₃-monolayer-based superlattice

Heng-Jui Liu^1*, 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, email:hengjui0109@dragon.nchu.edu.tw

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