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ReMo binary alloy films with a maximum Mo content of 25 at. % are successfully electrodeposited using high concentration acetate solutions in the presence of citric acid. The electrochemical behavior of the ReMo alloy is studied using cyclic voltammetry and anodic stripping methods. Different techniques, including electron microscopy, x-ray diffraction, and four-point probe resistance measurements at cryogenic temperature, are used to characterize the surface morphology, crystal structure, and superconducting critical temperature of alloys, respectively. While all films exhibit a crystalline hcp phase after 700 °C annealing, the film with the highest 25 at. % Mo content shows a second crystalline cubic phase. Mo doping preserves the enhanced superconducting transition temperature (Tc) in electrodeposited amorphous Re films and improves the stability of Tc against thermal annealing at a temperature of 200 °C. This is the first successful demonstration to use a dopant to stabilize the enhanced Tc of electrodeposited films, enabling the fabrication and operation of superconducting connectors above the intrinsic Tc of the materials. 

Perovskite oxide heterostructures host a large number of interesting phenomena such as ferroelectricity, which are often driven by octahedral distortions in the crystal that may induce polarization. SrHfO3 (SHO) is a perovskite oxide with a pseudocubic lattice parameter of 4.08 Å that previous density functional theory (DFT) calculations suggest can be stabilized in a ferroelectric P4mm phase when stabilized with sufficient compressive strain. Additionally, it is insulating and possesses a large band gap and a high dielectric constant, making it an ideal candidate for oxide electronic devices. To test the viability of epitaxial strain as a driver of ferroic phase transitions, SHO films were grown by hybrid molecular beam epitaxy (hMBE) with a tetrakis(ethylmethylamino)hafnium(IV) source on GdScO3 and TbScO3 substrates. Strained SHO phases were characterized using X-ray diffraction, X-ray absorption spectroscopy, and scanning transmission electron microscopy to determine the space group of the strained films, with the results compared to those of DFT-optimized models of phase stability versus strain. Contrary to past reports, we find that compressively strained SrHfO3 undergoes octahedral tilt distortions without associated ferroelectric polarization and most likely takes on the I4/mcm phase with the a0a0c– tilt pattern. 

The discovery of atomic monolayer magnetic materials has stimulated intense research activities in the two-dimensional (2D) van der Waals (vdW) materials community. The field is growing rapidly and there has been a large class of 2D vdW magnetic compounds with unique properties, which provides an ideal platform to study magnetism in the atomically thin limit. In parallel, based on tunneling magnetoresistance and magneto-optical effect in 2D vdW magnets and their heterostructures, emerging concepts of spintronic and optoelectronic applications such as spin tunnel field-effect transistors and spin-filtering devices are explored. While the magnetic ground state has been extensively investigated, reliable characterization and control of spin dynamics play a crucial role in designing ultrafast spintronic devices. Ferromagnetic resonance (FMR) allows direct measurements of magnetic excitations, which provides insight into the key parameters of magnetic properties such as exchange interaction, magnetic anisotropy, gyromagnetic ratio, spin-orbit coupling, damping rate, and domain structure. In this review article, we present an overview of the essential progress in probing spin dynamics of 2D vdW magnets using FMR techniques. Given the dynamic nature of this field, we focus mainly on broadband FMR, optical FMR, and spin-torque FMR, and their applications in studying prototypical 2D vdW magnets. We conclude with the recent advances in laboratory- and synchrotron-based FMR techniques and their opportunities to broaden the horizon of research pathways into atomically thin magnets. 

Abstract 2D van der Waals (vdW) magnets open landmark horizons in the development of innovative spintronic device architectures. However, their fabrication with large scale poses challenges due to high synthesis temperatures (>500 °C) and difficulties in integrating them with standard complementary metal‐oxide semiconductor (CMOS) technology on amorphous substrates such as silicon oxide (SiO₂) and silicon nitride (SiN_x). Here, a seeded growth technique for crystallizing CrTe₂films on amorphous SiN_x/Si and SiO₂/Si substrates with a low thermal budget is presented. This fabrication process optimizes large‐scale, granular atomic layers on amorphous substrates, yielding a substantial coercivity of 11.5 kilo‐oersted, attributed to weak intergranular exchange coupling. Field‐driven Néel‐type stripe domain dynamics explain the amplified coercivity. Moreover, the granular CrTe₂devices on Si wafers display significantly enhanced magnetoresistance, more than doubling that of single‐crystalline counterparts. Current‐assisted magnetization switching, enabled by a substantial spin–orbit torque with a large spin Hall angle (85) and spin Hall conductivity (1.02 ×  10⁷ℏ/2e  Ω⁻¹  m⁻¹), is also demonstrated. These observations underscore the proficiency in manipulating crystallinity within integrated 2D magnetic films on Si wafers, paving the way for large‐scale batch manufacturing of practical magnetoelectronic and spintronic devices, heralding a new era of technological innovation.