Colloquium

Upcoming Colloquium

Magnetic Proximity Effects and Spin–Orbit Torque in Two-Dimensional Ferromagnet Heterostructures
Dr. Mark Lohmann, Caltech

February 2, 2026
11:00am in HSCI-105

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Two-dimensional van der Waals (vdW) ferromagnets have emerged as promising platforms for spintronic applications due to their stability and tunable magnetic properties down to the monolayer limit. Their layered nature enables the formation of high-quality heterostructures, providing opportunities to explore interfacial spin–orbit phenomena and to develop ultrathin spin–orbit torque magnetic random-access memory (SOTMRAM).

In this work, we investigate magnetic proximity effects and spin–orbit torque in heterostructures based on twodimensional ferromagnets. We first study the magnetic properties of the vdW ferromagnetic insulator Cr₂Ge₂Te₆ through electrical transport measurements in proximitymagnetized Pt. We then examine current-induced magnetization switching and quantify the SOT efficiency in heterostructures incorporating the metallic 2D ferromagnet Fe₃GeTe₂ (FGT). Results are presented for Pt/FGT heterostructures formed by sputtering Pt onto thin FGT flakes, followed by measurements on fully vdWassembled FGT/bulk-insulating Bi₂Se₃ heterostructures. Finally, we compare the SOT efficiency in Bi₂Se₃/NiFe heterostructures using bulk-insulating and bulkconducting Bi₂Se₃, highlighting the advantage of bulkinsulating topological insulators for SOT generation.

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