Significant perpendicular magnetic anisotropy in room-temperature layered ferromagnet of Cr-intercalated CrTe₂

Abstract

Magnetic anisotropy is an important characteristic of magnetic materials. Particularly, perpendicular magnetic anisotropy (PMA) is superior for the design of spintronic devices, with the advantages of scalability, endurance, thermal stability, and low switching current density. Although a series of two-dimensional (2D) or quasi-2D layered ferromagnets have been demonstrated, the room temperature intrinsic ferromagnets with PMA is rarely found. Here, we report PMA in a room-temperature layered ferromagnet of Cr-intercalated CrTe2. By self-intercalation of the native Cr atoms, the in-plane anisotropy of CrTe2 can be switched to PMA. Meanwhile, the Cr-intercalated CrTe2 crystal can be easily exfoliated into thin flakes with thickness ∼10 nm. Besides the robust PMA at room temperature, Cr-intercalated CrTe2 also exhibits high saturation magnetization (208 emu cm−3 at 300 K), large anomalous Hall angle (2.23% at 300 K) and giant anomalous Hall factor (∼0.18 at 300 K). These excellent properties are highly desired for applications, and make Cr-intercalated CrTe2 a distinguished candidate among all existing magnetic materials. Our work reveals a promising platform for spintronic devices and offers a new route for controlling the magnetic anisotropy in layered materials.

Observation of Néel-type skyrmions in acentric self-intercalated Cr1+δTe2

“…From this figure we observe that at 2 K the M ( H ) data saturate at a lower magnetic field when the field was applied along [0001], whereas it does not saturate even if a magnetic field as large as 70 kOe is applied perpendicular to [0001]. The origin of such a large perpendicular anisotropy could be attributed to the presence of a high concentration of intercalated Cr atoms 17 which is also supported by our calculations (see Figs. S8 and S9 and corresponding text in the SI).…”

Above-room-temperature strong intrinsic ferromagnetism in 2D van der Waals Fe3GaTe2 with large perpendicular magnetic anisotropy

“…Meanwhile, θ M is always larger than θ B which implies the magnetization is always tends to the out-of-plane direction regardless of the direction of the magnetic field, indicating a strong PMA in this few-layer Fe 3 GaTe 2 . The robust large K u in Fe 3 GaTe 2 bulk crystals and 2D few-layer nanosheet at room temperature is not only better than the conventional widely-used ferromagnetic thin films like CoFeB and Co 2 FeAl 1,19 , but also an order of magnitude larger than other vdW ferromagnetic crystals such as Cr-CrTe 2 (7.6 × 10 4 J/m 3 ) and CrTe 2 (4.9 × 10 4 J/m 3 ) 10,20 (Fig. 2h and Supplementary Table 4).…”

Van der Waals Superstructure and Twisting in Self-Intercalated Magnet with Near Room-Temperature Perpendicular Ferromagnetism

“…While many efforts have been focused on studying transition metal trihalides (e.g., CrI 3 ), ,,− they have often been shown to be unstable and degrade within minutes in air and/or when exposed to light, requiring either in situ measurements in an oxygen-free environment or encapsulation between protective layers to prevent deterioration. , Conversely, transition metal telluride compounds are expected to be relatively more stable in ambient conditions. Among various vdW magnetic tellurides, the binary chromium telluride 1T-CrTe 2 has a ferromagnetic ordering temperature T c above room temperature, − which is significantly higher than that of the previously studied ternary chromium tellurides Cr 2 X 2 Te 6 (X = Si, Ge). ,,− Furthermore, a colossal anomalous Hall conductivity was recently observed in 1T-CrTe 2 with simultaneously large anomalous Hall angles and electrical conductivities distinct from other anomalous Hall materials, making it an excellent candidate for spintronics applications. , By intercalating Cr atoms into the vdW gap between the CrTe 2 layers, as shown in Figure a, different chromium telluride compounds Cr 1+δ Te 2 (0 < δ ≤ 1) are created. These different Cr 1+δ Te 2 phases have a broad range of magnetic ordering temperatures and novel magnetic phases. ,,,− For example, CrTe (or Cr 2 Te 2 ) thin films have been reported to exhibit the topological Hall effect, noted as strong evidence of a magnetic skyrmion phase .…”

“…1,14,37−44 Furthermore, a colossal anomalous Hall conductivity was recently observed in 1T-CrTe 2 with simultaneously large anomalous Hall angles and electrical conductivities distinct from other anomalous Hall materials, making it an excellent candidate for spintronics applications. 33,45 By intercalating Cr atoms into the vdW gap between the CrTe 2 layers, as shown in Figure 1a, different chromium telluride compounds Cr 1+δ Te 2 (0 < δ ≤ 1) are created. These different Cr 1+δ Te 2 phases have a broad range of magnetic ordering temperatures and novel magnetic phases.…”