Heteroepitaxy of 2D CuCr₂Te₄ with Robust Room‐temperature Ferromagnetism

Abstract

Magnetic materials in 2D have attracted widespread attention for their intriguing magnetic properties. 2D magnetic heterostructures can provide unprecedented opportunities for exploring fundamental physics and novel spintronic devices. Here, the heteroepitaxial growth of ferromagnetic CuCr2Te4 nanosheets is reported on Cr2Te3 and mica by chemical vapor deposition. Magneto‐optical Kerr effect measurements reveal the thickness‐dependent ferromagnetism of CuCr2Te4 nanosheets on mica, where a decrease of Curie temperature (TC) from 320 to 260 K and an enhancement of perpendicular magnetic anisotropy with reducing thickness are observed. Moreover, lattice‐matched heteroepitaxial ultrathin CuCr2Te4 on Cr2Te3 exhibits an enhanced robust ferromagnetism with TC up to 340 K due to the interfacial charge transfer. Stripe‐type magnetic domains and single magnetic domain are discovered in this heterostructure with different thicknesses. The work provides a way to construct robust room‐temperature 2D magnetic heterostructures for functional spintronic devices.

Observation of Colossal Topological Hall Effect in Noncoplanar Ferromagnet Cr5Te6 Thin Films

“…In recent years, there has been great interest in the burgeoning low‐dimensional ferromagnetic materials, [ 25–27 ] such as the chromium telluride (Cr x Te y ) family, [ 28–34 ] Cr 2 Ge 2 Te 6 , [ 35 ] Fe 3 GeTe 2 , [ 36 ] Fe 5 GeTe 2 , [ 37 ] Fe 3 GaTe 2 , [ 38 ] and CuCr 2 Te 4 , [ 39 ] owing to their intrinsic high‐temperature ferromagnetism for versatile applications. [ 40 ] The emergent THE has been notably found in these low‐dimensional ferromagnetic systems, including their heterostructures (e.g., CrTe/SrTiO 3 , [ 41 ] Cr 2 Te 3 /Bi 2 Te 3 , [ 42 ] Fe 3 GeTe 2 /WTe 2 , [ 43 ] CrTe 2 /Bi 2 Te 3 , [ 44 ] and Cr 2 Te 3 /Cr 2 Se 3 [ 45 ] ), bulk forms (e.g., Cr 5 Te 8 , [ 46 ] Cr 0.9 B 0.1 Te, [ 47 ] Cr 0.87 Te, [ 48 ] and Cr 1.53 Te 2 [ 49 ] ), nanosheets (e.g., Cr 5 Si 3 [ 50 ] ), and exfoliated nanoflakes (e.g., Cr 1.2 Te 2 [ 51 ] ), demonstrating their potential applications in chiral spintronics.…”

High‐Speed Optoelectronic Nonvolatile Memory Based on van der Waals Heterostructures

“…In recent years, ultrathin layered 2D crystals such as graphene, hBN, TMDs and their heterostructures have been receiving much attention because of their ideal DOI: 10.1002/smll.202304730 atomically flat surface, excellent interface matching, and immunity to short-channel effects. [3][4][5][6] Various types of memories based on van der Waals heterostructures have been reported, including floating-gate memory, [7][8][9][10] memristor, [11,12] ferroelectric memory, [13][14][15][16] carrier trapping memory, [17][18][19][20] magnetic spinvalves memory, [21][22][23] and phase-change memory. [24] Among these, floating-gate memory based on 2D crystals has exhibited promising results, demonstrating improved data retention and excellent endurance properties compared to other types of memories.…”

2D Materials by Design: Intercalation of Cr or Mn between two VSe2 van der Waals Layers

“…10,11,14 Bulk-exfoliated sheets or thin films of these materials have demonstrated important phenomena, such as concentration-dependent magnetic anisotropy 6 and skyrmion lattices in Cr 1+δ Te 2 , 12,13 magnetic properties of self-intercalated TaS 2 14 and in VSe 2 15 and VTe 2 , 16 proposed superconductivity in Ni 1+δ Te 2 , 17 layer-dependent magnetism in CrCuSe 2 , 5 and demonstration of heteroepitaxy of CuCr 2 Te 4 . 18 In contrast to these reports, a novel synthesis approach is discussed here that enables incorporation of various TMs between TMD sheets. The methodology can be described by a two-step process: (i) synthesis of ultrathin TMD sheets and (ii) intercalation of TM between the TMD layers.…”

“…For different concentrations, in-plane ordered 2 × 2, √3 × √3 R30°, or 2 × 1 superstructures are known . Previous studies of ultrathin pseudo 2D crystals of this class are based on known bulk phases or self-intercalation compounds (i.e., only one kind of TM). ,, Bulk-exfoliated sheets or thin films of these materials have demonstrated important phenomena, such as concentration-dependent magnetic anisotropy and skyrmion lattices in Cr 1+δ Te 2 , , magnetic properties of self-intercalated TaS 2 and in VSe 2 and VTe 2 , proposed superconductivity in Ni 1+δ Te 2 , layer-dependent magnetism in CrCuSe 2 , and demonstration of heteroepitaxy of CuCr 2 Te 4 . In contrast to these reports, a novel synthesis approach is discussed here that enables incorporation of various TMs between TMD sheets.…”