Tunable Room-Temperature Ferromagnetism in Two-Dimensional Cr<sub>2</sub>Te<sub>3</sub>.

Wen, Yao; Liu, Zhehong; Zhang, Yu; Xia, Congxin; Zhai, Baoxing; Zhang, Xinhui; Zhai, Guihao; Shen, Chao et al. · Nano Lett · 2020

basic_science · Level V

Where this comes from

Abstract

The manipulation of magnetism provides a unique opportunity for the development of data storage and spintronic applications. Until now, electrical control, pressure tuning, stacking structure dependence, and nanoscale engineering have been realized. However, as the dimensions are decreased, the decrease of the ferromagnetism phase transition temperature (<i>T</i><sub>c</sub>) is a universal trend in ferromagnets. Here, we make a breakthrough to realize the synthesis of 1 and 2 unit cell (UC) Cr<sub>2</sub>Te<sub>3</sub> and discover a room-temperature ferromagnetism in two-dimensional Cr<sub>2</sub>Te<sub>3</sub>. The newly observed <i>T</i><sub>c</sub> increases strongly from 160 K in the thick flake (40.3 nm) to 280 K in 6 UC Cr<sub>2</sub>Te<sub>3</sub> (7.1 nm). The magnetization and anomalous Hall effect measurements provided unambiguous evidence for the existence of spontaneous magnetization at room temperature. The theoretical model revealed that the reconstruction of Cr<sub>2</sub>Te<sub>3</sub> could result in anomalous thickness-dependent <i>T</i><sub>c</sub>. This dimension tuning method opens up a new avenue for manipulation of ferromagnetism.