Magnetic Anisotropy Modulation via van der Waals Gap Engineering in 2D Ferromagnet Fe₄GeTe₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Magnetic anisotropy modulation is crucial for spintronics applications.
• Two-dimensional ferromagnetic materials (2D FMs) offer tunable properties for magnetic control.
• The van der Waals (vdW) gap in 2D FMs is a promising but poorly understood area for anisotropy modulation.

Purpose of the Study:

• To investigate the impact of epitaxial growth on the vdW gap and magnetic anisotropy of 2D FMs.
• To elucidate the microscopic mechanisms behind interface-induced magnetic anisotropy changes.
• To explore interface gap engineering as a strategy for tailoring magnetic properties in 2D FMs.

Main Methods:

• Epitaxial growth of α-Al2O3 on Fe4GeTe2.
• Characterization of the vdW gap expansion using advanced techniques.
• Experimental and theoretical analyses of magnetic anisotropy and spin reorientation temperature (TSR).

Main Results:

• Epitaxial growth induced a significant vdW gap expansion (up to 0.51 Å) at the α-Al2O3/Fe4GeTe2 interface.
• This expansion robustly enhanced in-plane magnetic anisotropy (IMA) and suppressed TSR from 288 K.
• The observed behavior contrasted with conventional thickness-dependent perpendicular magnetic anisotropy (PMA).

Conclusions:

• Interface gap engineering is a novel and effective method for tuning magnetic anisotropy in 2D FMs.
• vdW gap expansion reduces orbital overlap, diminishing PMA.
• Findings advance the design principles for next-generation spintronic devices leveraging 2D FMs.