Magnetic Anisotropy in Two-dimensional van der Waals Magnetic Materials and Their Heterostructures: Importance, Mechanisms, and Opportunities

TL;DR

This review highlights the critical role of magnetic anisotropy in stabilizing 2D magnetism in van der Waals materials, discussing mechanisms, engineering approaches, and future opportunities for spintronic applications.

Contribution

It provides a comprehensive overview of the mechanisms and engineering strategies to control magnetic anisotropy in 2D vdW magnetic materials, advancing understanding for future applications.

Findings

Magnetic anisotropy is essential for 2D magnetic order.

Ligand spin-orbit coupling influences anisotropy.

Various engineering methods can tune magnetic properties.

Abstract

Two-dimensional (2D) magnetism in atomically thin van der Waals (vdW) monolayers and heterostructures has attracted significant attention due to its promising potential for next-generation spintronic and quantum technologies. A key factor in stabilizing long-range magnetic order in these systems is magnetic anisotropy, which plays a crucial role in overcoming the limitations imposed by the Mermin-Wagner theorem. This review provides a comprehensive theoretical and experimental overview of the importance of magnetic anisotropy in enabling intrinsic 2D magnetism and shaping the electronic, magnetic, and topological properties of 2D vdW materials. We begin by summarizing the fundamental mechanisms that determine magnetic anisotropy, emphasizing the contributions from strong ligand spin-orbit coupling of ligand atoms and unquenched orbital magnetic moments. We then examine a range of material engineering approaches, including alloying, doping, electrostatic gating, strain, and pressure, that have been employed to effectively tune magnetic anisotropy in these materials. Finally, we discuss open challenges and promising future directions in this rapidly advancing field. By presenting a broad perspective on the role of magnetic anisotropy in 2D magnetism, this review aims to stimulate ongoing efforts and new ideas toward the realization of robust, room-temperature applications based on 2D vdW magnetic materials and their heterostructures.