Ferromagnetism in two-dimensional CrTe2 epitaxial films down to a few atomic layers

Abstract

Two-dimensional (2D) van der Waals ferromagnetic materials have attracted intense attention due to their potential impact on both fundamental and applied research studies. Recently, a new 2D ferromagnet CrTe2, prepared by mechanical exfoliation or chemical vapor deposition, has gained interest due to its novel magnetic properties. In this work, high quality CrTe2 epitaxial thin films were prepared on GaAs (111)B substrates using solid source molecular beam epitaxy, with the thickness varying from 35 to 4 monolayers (MLs). The magnetic easy axis of all the films is oriented along the c-axis. A Curie temperature of 205 K is found in the 35 ML CrTe2 film, measured by the temperature-dependent anomalous Hall resistance (RAHE). Importantly, even when the film thickness decreases to 4 MLs, a robust out-of-plane ferromagnetism with a Curie temperature of 191 K has been demonstrated. This finding could pave the way for investigating the fundamental studies in 2D ferromagnetism and has great significance in device applications.

Emergent Topological Hall Effect from Exchange Coupling in Ferromagnetic Cr2Te3/Noncoplanar Antiferromagnetic Cr2Se3 Bilayers

“…Such nonmonotonous temperature dependence and sign-reversal were observed in some FM materials, including Cr−Te compounds, and interpreted as a result of delicate Berry curvature dependence on the exchange stiffness. 14,33,37 Our DFT calculations show such a sign-reversal in the intrinsic σ xy near the Fermi energy (Figure S5). The most striking effects of CS proximity were the drastic suppression of the AHE and the appearance of the THE, as shown in Figure 2b.…”

Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

“…However, the magnetization of CT/ BSTS has almost saturated under 100 K (Fig. 1d), and the anomalous Hall resistance is limited by R s which is determined by both the mechanism of AHE and the longitudinal resistivity [12,[38][39][40]. So, the decrease of ρ xy of CT could be accounted for both the decrease in R sh of the CT film (Fig.…”

ZrTe2/CrTe2: an epitaxial van der Waals platform for spintronics

“…This persists even in flakes exfoliated down to thicknesses of tens of nanometers 28 – 31 . Synthesized epitaxial thin films of this material also show a relatively high T c down to the quasi-2D regime 32 , 33 . An in-plane-to-out-of-plane transition of the magnetic easy axis in 1T-CrTe 2 may be controlled through thickness and strain in thin films 34 , 35 .…”