Layer-Number-Independent Two-Dimensional Ferromagnetism in Cr₃Te₄

Abstract

In a conventional magnetic material, a long-range magnetic order develops in three dimensions, and reducing a layer number weakens its magnetism. Here we demonstrate anomalous layer-number-independent ferromagnetism down to the two-dimensional (2D) limit in a metastable phase of Cr3Te4. We fabricated Cr3Te4 thin films by molecular-beam epitaxy and found that Cr3Te4 could host two distinct ferromagnetic phases characterized with different Curie temperatures (T C). One is the bulk-like “high-T C phase” showing room-temperature ferromagnetism, which is consistent with previous studies. The other is the metastable “low-T C phase” with T C ≈ 160 K, which exhibits a layer-number-independent T C down to the 2D limit in marked contrast with the conventional high-T C phase, demonstrating a purely 2D nature of its ferromagnetism. Such significant differences between two distinct phases could be attributed to a small variation in the doping level, making this material attractive for future ultracompact spintronics applications with potential gate-tunable room-temperature 2D ferromagnetism.

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.…”

Controlled Growth of Submillimeter-Scale Cr5Te8 Nanosheets and the Domain Wall Nucleation Governed Magnetization Reversal Process

“…Even if it is possible for the van der Waals material of CrTe 2 to be fabricated by mechanical exfoliation, it is always difficult to obtain CrTe 2 nanosheets with large lateral size and uniform thickness. Although Cr x Te y thin films were already successfully grown by MBE, − such a sophisticated method is of high cost for mass production. The economical and controllable CVD method is the primary preparation method of Cr x Te y at present; only several groups have synthesized 2D Cr 5 Te 8 crystals using CVD in recent years, ,,, but the production of large-sized and ultrathin 2D Cr 5 Te 8 nanosheets remains elusive, not to mention the controllable synthesis.…”

Opportunities of Advanced Physical Studies at the Hefei Advanced Light Facility

“…The superior sensitivity for weak magnetism allows for the study of previously undetectable weak magnetic phenomena and opens new possibilities for understanding the intricate spin behaviors in materials and devices. [26][27][28][29] The spatial resolution of 3 µm will provide researchers with the ability to investigate magnetic inter-actions and phenomena at the microscopic level. FMR and PEEM techniques will be incorporated into the toolbox and enable the study of spin dynamics or spin current torque devices.…”