Emergent Global-Pinning Exchange Bias in van der Waals Magnetic Heterostructures

Area of Science:

• Spintronics
• Materials Science
• Condensed Matter Physics

Background:

• Magnetoresistive random access memory (MRAM) is crucial for AI applications, demanding cost-effective and miniaturized solutions.
• Van der Waals (vdW) magnets offer potential for high-performance, scalable memory devices through vertical stacking.
• Current vdW magnet device architectures face challenges with perfect alignment and interface interactions, leading to complexity and high power consumption.

Purpose of the Study:

• To address challenges in vdW magnet device design by proposing a new configuration with partial overlap.
• To achieve a global-pinning exchange bias (GPEB) effect in vdW heterostructures for enhanced memory performance.
• To expand design flexibility and explore new strategies for in-memory computing devices.

Main Methods:

• Utilized Fe3GeTe2/MnBi2Te4 (FGT/MBT) vdW heterostructures as a model system.
• Investigated the global-pinning exchange bias (GPEB) effect in a partially overlapped device configuration.
• Employed theoretical modeling to confirm magnetic couplings and the GPEB phenomenon.

Main Results:

• Successfully achieved a global-pinning exchange bias (GPEB) effect with a horizontal pinning distance of approximately 100 µm.
• Demonstrated that a small-area MnBi2Te4 (MBT) layer on Fe3GeTe2 (FGT) fully biases the entire FGT layer due to inherent magnetic couplings.
• Showcased the prevalence of the GPEB effect across various vdW heterostructures, with interlayer coupling and coverage ratio as tunable parameters.

Conclusions:

• The partial overlap device configuration offers enhanced design flexibility for vdW magnet-based memory devices.
• The emergent GPEB effect provides a promising scheme for constructing advanced in-memory computing devices.
• This work opens new avenues for future spintronic applications by enabling efficient and scalable memory solutions.