The van der Waals magnets CrX3(X = I, Br, and Cl) exhibit highly tunable magnetic properties and are promising candidates for developing novel two‐dimensional (2D) spintronic devices such as magnetic tunnel junctions and spin tunneling transistors. Previous studies of the antiferromagnetic CrCl3have mainly focused on mechanically exfoliated samples. Controlled synthesis of high quality atomically thin flakes is critical for their technological implementation but has not been achieved to date. This work reports the growth of large CrCl3flakes down to monolayer thickness via the physical vapor transport technique. Both isolated flakes with well‐defined facets and long stripe samples with the trilayer portion exceeding 60 µm have been obtained. High‐resolution transmission electron microscopy studies show that the CrCl3flakes are single crystalline in the monoclinic structure, consistent with the Raman results. The room temperature stability of the CrCl3flakes decreases with decreasing thickness. The tunneling magnetoresistance of graphite/CrCl3/graphite tunnel junctions confirms that few‐layer CrCl3possesses in‐plane magnetic anisotropy and Néel temperature of 17 K. This study paves the path for developing CrCl3‐based scalable 2D spintronic applications.
Large‐scale, polycrystalline WTe2thin films are synthesized by atmospheric chemical vapor reaction of W metal films with Te vapor catalyzed by H2Te intermediates, paving a way to understanding the synthesis mechanism for low bonding energy tellurides and toward synthesis of single‐crystalline telluride nanoflakes. Through‐plane and in‐plane thermal conductivities of single‐crystal WTe2flakes and polycrystalline WTe2thin films are measured for the first time. Nanoscale grains and disorder in WTe2thin films suppress the in‐plane thermal conductivity of WTe2greatly, which is at least 7.5 times lower than that of the single‐crystalline flakes.
more » « less- NSF-PAR ID:
- 10030957
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 27
- Issue:
- 8
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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