Enhanced Magnetism and Anomalous Hall Transport through Two-Dimensional Tungsten Disulfide Interfaces

Abstract

The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these systems is lacking. In this study, the MPE has been probed in Pt/WS2/BPIO (biphase iron oxide, Fe3O4 and a-Fe2O3) heterostructures through a comprehensive investigation of their magnetic and transport properties using magnetometry, four-probe resistivity, and anomalous Hall effect (AHE) measurements. Density functional theory (DFT) calculations are performed to complement the experimental findings. We found that the presence of monolayer WS2 flakes reduces the magnetization of BPIO and hence the total magnetization of Pt/WS2/BPIO at T > ~120 K—the Verwey transition temperature of Fe3O4 (TV). However, an enhanced magnetization is achieved at T < TV. In the latter case, a comparative analysis of the transport properties of Pt/WS2/BPIO and Pt/BPIO from AHE measurements reveals ferromagnetic coupling at the WS2/BPIO interface. Our study forms the foundation for understanding MPE-mediated interfacial properties and paves a new pathway for designing 2D TMD/magnet heterostructures for applications in spintronics, opto-spincaloritronics, and valleytronics.

Transition Metal Dichalcogenides: Making Atomic‐Level Magnetism Tunable with Light at Room Temperature

“…Due to their high-quality interfaces and weakly coupled interlayer interactions, 2D-TMDs with desirable properties can be easily stacked together, creating 2D vdW heterostructures with unique properties otherwise absent in their individual components. [7,47,[77][78][79][80][81][82][83][84][85] Their potential for next-generation spintronic, opto-spintronic, opto-spincaloritronic, and valleytronic device applications has been emphasized, owing to their atomically thin nature and integrated opto-electro-magnetic properties. [7,[82][83][84][85] Figure 1 illustrates the potential applications of 2D-TMD DMSs and their heterostructures.…”

“…The true appeal of 2D-TMD DMSs for these applications stems from their magnetic tunability in response to external stimuli (electric gating, light, and strain). Magnetic state tunability of a 2D-TMD can range from enhancing its magnetic moment, and tuning its Curie temperature to inducing magnetism in non-magnetic materials through chemical doping, [52][53][54][55]63,[86][87][88] defect engineering, [60] phase change or structure engineering, [75,89,90] interface engineering, [47,[77][78][79][80][81] or applying external stimuli. [56,57,91] Various strategies for enhancing magnetic functionalities in 2D-TMDs have been highlighted in recent review articles.…”

Valley-Selective Polarization in Twisted Bilayer Graphene Controlled by a Counter-Rotating Bicircular Laser Field

“…Valleytronics aims to manipulate the motion of electrons to induce valley polarization, a novel quantum degree of freedom that carries information and can be achieved by breaking spatial symmetry [11,12]. Over the past decade, significant progress has been made in both theoretical and experimental studies on valley-related transport properties [13][14][15]. In addition, various optical-driven approaches have been proposed to achieve transient valley polarization [16][17][18][19].…”