Interface Engineering of Magnetic Anisotropy in van der Waals Ferromagnet-based Heterostructures

Abstract

Interface engineering is an effective approach to tune the magnetic properties of van der Waals (vdW) magnets and their heterostructures. The prerequisites for the practical utilization of vdW magnets and heterostructures are a quantitative analysis of their magnetic anisotropy and the ability to modulate their interfacial properties, which have been challenging to achieve with conventional methods. Here we characterize the magnetic anisotropy of Fe3GeTe2 layers by employing the magnetometric technique based on anomalous Hall measurements and confirm its intrinsic nature. In addition, on the basis of the thickness dependences of the anisotropy field, we identify the interfacial and bulk contributions. Furthermore, we demonstrate that the interfacial anisotropy in Fe3GeTe2-based heterostructures is locally controlled by adjacent layers, leading to the realization of multiple magnetic behaviors in a single channel. This work proposes that the magnetometric technique is a useful platform for investigating the intrinsic properties of vdW magnets and that functional devices can be realized by local interface engineering.

High-Quality Ferromagnet Fe3GeTe2 for High-Efficiency Electromagnetic Wave Absorption and Shielding with Wideband Radar Cross Section Reduction

“…Deng et al used an ionic gate to raise the Curie temperature (Tc) of trilayer FGT to room temperature, which is much higher than the bulk Tc. According to the topics covered by most studies focused on fundamental magnetic physics and spintronic devices, − FGT as a candidate will have promising applications in the next generation of Opto-electromagnetic information science and technology. However, high-quality FGT single crystal to date has been generally synthesized with a small quantity, which greatly limits the in-depth property research and potential applications.…”

2D Magnetic Semiconductor Fe3GeTe2 with Few and Single Layers with a Greatly Enhanced Intrinsic Exchange Bias by Liquid-Phase Exfoliation

“…However, the insufficiency of a stable mass production technology and integrated intrinsic nature development is usually a huge obstacle that restricts the in-depth research and applications of emerging materials. Currently, the typical preparation methods of 2D FGT are mechanical exfoliation − ,− and molecular beam epitaxy. − For example, an FGT nanodevice was made by repeatedly exfoliating FGT crystals via Scotch tape and then carefully transferred to pretreated electrodes after attaching to a PDMS stamper . Liu et al obtained a 2D FGT film under a vacuum of 2.5 × 10 –9 Torr through a molecular beam epitaxy system equipped with a crystal oscillator and in situ reflection high energy electron diffraction system.…”

“…22 Deng et al 40 increased the T C of mechanically exfoliated atomically thin FGT to room temperature through an ionic gate, much higher than that of bulk crystals. Kim et al 33 showed that the interfacial vdW materials (h-BN, WSe 2 ) on FGT can locally tune the perpendicular magnetic anisotropy of heterostructure systems, leading to multiple magnetic behaviors in a single channel. However, the insufficiency of a stable mass production technology and integrated intrinsic nature development is usually a huge obstacle that restricts the in-depth research and applications of emerging materials.…”

“…Deng et al increased the T C of mechanically exfoliated atomically thin FGT to room temperature through an ionic gate, much higher than that of bulk crystals. Kim et al showed that the interfacial vdW materials (h-BN, WSe 2 ) on FGT can locally tune the perpendicular magnetic anisotropy of heterostructure systems, leading to multiple magnetic behaviors in a single channel.…”

“…Fe 3 GeTe 2 (FGT) with 2D intrinsic ferromagnetism, a higher Curie temperature ( T C ), − and slower oxidation process , has become a promising candidate for next-generation 2D magnetic devices. Since FGT was reported in 2006, extensive research has been performed in simulation calculations and structural design based on the visualization and manipulation of magnetic domains, − magnetically controllable regulation, − heterostructure correlation magnetism properties, − and others. − For example, the stripy domains, double-walled domains, and bubble domains in FGT were directly observed with the nickel tip of a scanning tunneling microscope and realized the transition between domains . Deng et al increased the T C of mechanically exfoliated atomically thin FGT to room temperature through an ionic gate, much higher than that of bulk crystals.…”