Imaging the Magnetic Anisotropy in Ultrathin Fe4GeTe2 with a Nitrogen-Vacancy Magnetometer
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2024-05-06 |
| Journal | Nano Letters |
| Authors | Chen Wang, Siyuan Wan, Ya Wang, Fazhan Shi, Ming Gong |
| Institutions | Nanchang University, University of Science and Technology of China |
| Citations | 5 |
Abstract
Section titled āAbstractāTwo-dimensional (2D) Fe<sub><i>n</i></sub>GeTe<sub>2</sub>, with <i>n</i> = 3, 4, and 5, has been realized in experiments, showing strong magnetic anisotropy with enhanced critical temperature (<i>T</i><sub>c</sub>). The understanding of its magnetic anisotropy is crucial for the exploration of more stable 2D magnets and its spintronic applications. Here, we report a quantitative reconstruction of the magnetization magnitude and its direction in ultrathin Fe<sub>4</sub>GeTe<sub>2</sub> using nitrogen vacancy centers. Through imaging stray magnetic fields, we identified the spin-flop transition at approximately 80 K, resulting in a change of the easy axis from the out-of-plane direction to the in-plane direction. Moreover, by analyzing the thermally activated escape behavior of the magnetization near <i>T</i><sub>c</sub> in terms of the Ginzburg-Landau model, we observed the in-plane magnetic anisotropy effect and the formation capability of magnetic domains at ā¼0.4 Ī¼m<sup>2</sup> Ī¼T<sup>-1</sup>. Our findings contribute to the quantitative understanding of the magnetic anisotropy effect in a vast range of 2D van der Waals magnets.