Engineering magnetic anisotropy in two-dimensional systems has enormous scientific and technological implications. The uniaxial anisotropy universally exhibited by two-dimensional magnets has only two stable spin directions, demanding 180 degrees spin switching between states. We demonstrate a novel eightfold anisotropy in magnetic SrRuO3 monolayers by inducing a spin reorientation in (SrRuO3)1/(SrTiO3)N superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial <001> direction (N = 1 and 2) to eightfold <111> directions (N = 3, 4 and 5). This eightfold anisotropy enables 71 and 109 degrees spin switching in SrRuO3 monolayers, analogous to 71 and 109 degrees polarization switching in ferroelectric BiFeO3. First-principle calculations reveal that increasing the SrTiO3 layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO3 monolayer easy axis. Our work demonstrates that correlation effects can be exploited to substantially change spin-orbit interactions, stabilizing unprecedented properties in two-dimensional magnets and opening rich opportunities for low-power, multi-state device applications.
@article{arxiv.2004.10939,
title = {Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer},
author = {Zhangzhang Cui and Alexander J. Grutter and Hua Zhou and Hui Cao and Yongqi Dong and Dustin A. Gilbert and Jingyuan Wang and Yi-Sheng Liu and Jiaji Ma and Zhenpeng Hu and Jinghua Guo and Jing Xia and Brian J. Kirby and Padraic Shafer and Elke Arenholz and Hanghui Chen and Xiaofang Zhai and Yalin Lu},
journal= {arXiv preprint arXiv:2004.10939},
year = {2020}
}
Comments
15+13 pages, 5+10 figures, including supplementary materials