Abstract
Two-dimensional (2D) magnets with intrinsic ferromagnetic/antiferromagnetic (FM/AFM) ordering are highly desirable for future spintronic devices. However, the direct growth of their crystals is in its infancy. Here we report a chemical vapor deposition approach to controllably grow layered tetragonal and non-layered hexagonal FeTe nanoplates with their thicknesses down to 3.6 and 2.8 nm, respectively. Moreover, transport measurements reveal these obtained FeTe nanoflakes show a thickness-dependent magnetic transition. Antiferromagnetic tetragonal FeTe with the Néel temperature (TN) gradually decreases from 70 to 45 K as the thickness declines from 32 to 5 nm. And ferromagnetic hexagonal FeTe is accompanied by a drop of the Curie temperature (TC) from 220 K (30 nm) to 170 K (4 nm). Theoretical calculations indicate that the ferromagnetic order in hexagonal FeTe is originated from its concomitant lattice distortion and Stoner instability. This study highlights its potential applications in future spintronic devices.
Highlights
Two-dimensional (2D) magnets with intrinsic ferromagnetic/antiferromagnetic (FM/atomic force microscopy (AFM)) ordering are highly desirable for future spintronic devices
The antiferromagnetic behavior of tetragonal FeTe is exhibited with a TN decreases as the thickness decline, while the ferromagnetic hexagonal FeTe is displayed with a thicknessdependent TC
During the CVD process, the Ar and H2 mixture carries a certain amount of tellurium vapor at a fixed heating temperature of tellurium source (TTe) to react with evaporated FeCl2 at different growth temperatures (Tgrowth) to produce different phases
Summary
Two-dimensional (2D) magnets with intrinsic ferromagnetic/antiferromagnetic (FM/AFM) ordering are highly desirable for future spintronic devices. It is challenging to identify an exact phase of these 2D magnets and provide a sound explanation for the origin of its magnetism Selective substrates, such as mica, were chosen for the growth of a few of 2D magnets, including ultrathin Cr2S3 and CrSe crystals[11,12]. The conventional phase of FeTe is an antiferromagnetic metal with a tetragonal crystal structure and TN ≈ 70 K16. By controlling the growth temperature, ultrathin 2D-layered tetragonal FeTe nanoplates and non-layered hexagonal FeTe nanoplates were selectively obtained as square or triangular shapes, with thicknesses down to 2.8 and 3.6 nm, respectively. The antiferromagnetic behavior of tetragonal FeTe is exhibited with a TN decreases as the thickness decline, while the ferromagnetic hexagonal FeTe is displayed with a thicknessdependent TC. Theoretical calculations indicate that the structural distortion is responsible for the observed ferromagnetism
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
