The recent discovery of van der Waals two-dimensional magnetic materials has stimulated research on emergent low dimensional magnetic phenomena in these materials. Furthermore, many spintronic devices utilizing two-dimensional magnetic materials have been realized. Two-dimensional magnets offer several unique characteristics and advantages compared to ultra-thin magnetic films, which has been the material-of-choice for spintronic applications. Heterostructures and twisted lattices between two-dimensional magnets and various families of two-dimensional materials, with clean and well-defined interfaces, can be fabricated, which enable interfacial engineering of many magnetic properties. In addition, the weak layer-to-layer coupling suggest that spin transport properties of the layered materials might be distinct from conventional magnetic thin films. In this review article, we highlight selected research results in two-dimensional-magnet-based spintronics, focusing on spin valves, magnetic tunnel junctions, spin filter devices, and spin-orbit torque devices.

Recent advancements in spintronics have focused on materials with strong spin-orbit coupling, such as topological insulators and Weyl semimetals, which offer new methods for controlling spin currents. This study investigates the magnetic proximity effect in a NbIrTe₄/Ni₈₁Fe₁₉ (Permalloy) heterostructure. Results show that crystallographic orientation of NbIrTe₄ induces uniaxial magnetic anisotropy in Permalloy, influenced by strong spin-orbit coupling in NbIrTe₄. This research enhances the understanding of magnetic interactions in Weyl semimetal/magnet heterostructure and promises advancements in low-power electronic devices and magnetic memory, improving the speed, size, and energy efficiency of spintronic technologies.

Ellipsometer is a measurement device that obtains information about the thickness and refractive index of a thin film by utilizing the polarization of light. Since the light used here generally consists of continuous waves, only static information could be obtained. In this paper, I present the instrumentation of a femtosecond time-resolved ellipsometer based on a pump-probe technique using femtosecond laser pulses. The femtosecond pump laser induces ultrafast changes in properties of the material, and the probe laser measures information such as the refractive index of the sample altered by strain or heat. I expect to provide meaningful information that can infer the interaction mechanisms over time between the electron, lattice, and spin systems of the material.