Room temperature weak ferromagnetism in Sn1−xMnxSe2 2D films grown by molecular beam epitaxy

Abstract

We discuss growth and magnetic properties of high-quality two dimensional (2D) Sn1−xMnxSe2 films. Thin films of this 2D ternary alloy with a wide range of Mn concentrations were successfully grown by molecular beam epitaxy. Mn concentrations up to x ≈ 0.60 were achieved without destroying the crystal structure of the parent SnSe2 2D system. Most important, the specimens show clear weak ferromagnetic behavior above room temperature, which should be of interest for 2D spintronic applications.

Molecular Beam Epitaxy and High-Pressure Studies of van der Waals Magnets

“…Many previous studies have tried various ways to induce ferromagnetic ordering into non-magnetic 2D van der Waals materials. This includes various types of defect engineering [72,73,74,75,76,77,78,79], induced magnetism via strain [80], compositional alloying [71], or the proximity effect [16,17,81] to induce a magnetic moment at the interface of the non-magnetic 2D material.…”

“…A few years later, scientists began studying the effects of depositing magnetic impurities into non-magnetic 2D semiconductors during MBE growth [71,82,83]. There has been many theoretical predictions about magnetic doping of Mn, Cr, and V into TMDCs such as MoS 2 [84], which is a motivating factor for attempting these studies.…”

“…There has been many theoretical predictions about magnetic doping of Mn, Cr, and V into TMDCs such as MoS 2 [84], which is a motivating factor for attempting these studies. One would expect similarities to 3D semiconductors such as Ga [71]. They showed that with up to ∼70% of Mn impurities, the crystal structure of SnSe 2 is unchanged and they are able to observe a weak ferromagnetic moment up to room temperature of about ∼0.09 µ B .…”

Electron Spin Dynamics of Two‐Dimensional Layered Materials

“…Molecular beam epitaxy (MBE) was also demonstrated to prepare high‐quality epitaxial films on graphene‐terminated 6H‐SiC(0001) substrate . MBE also allowed for the fine control of non‐stoichiometric phase preparation . There are many other methods to synthesise layered TMDs, for example ultrasonication in solvents, physical vapor deposition, hydrothermal synthesis, and more recently, Tedstone et al described a number of methods to synthesise TMD materials with transition‐metal dopants.…”

“…Intercalating Mn into MoS 2 monolayers has been reported with doping levels of ∼2 at% Mn, however this caused a loss of two‐dimensionality due to competing MnS 3‐dimensional structures. Nevertheless, weak ferromagnetism in Sn 1‐ x Mn x Se 2 , even at room temperature has been reported . Cheng et al demonstrated that several transition metals can be incorporated to WS 2 nanoflakes, and while their doping with Gd 3+ was employed for magnetic resonance imaging, one could easily envision translating such materials into spintronic applications.…”