Sharma, M., Ojha, B., Mohanty, S. et al.

Study of the domain wall (DW) dynamics in ultrathin films with perpendicular magnetic anisotropy (PMA) opens the way to envisage the low-power and high-performance memory and logic devices. Here, we have studied the magnetization reversal and DW dynamics of Pt/Co/Pt ultrathin films having PMA. The Pt/Co/Pt ultrathin trilayers have been fabricated using molecular beam epitaxy (MBE) at room temperature. The DW velocity measurements were performed by bubble domain expansion method with an additional homemade coil in order to apply out-of-plane (OOP) field in the polar magneto-optic Kerr effect (P-MOKE)-based microscope. The DW motion is limited only in creep regime, and the maximum observed DW velocity is 32 mm/s. Further, it has been shown that the DW velocity can be enhanced via increasing Co thickness.

J. Hrdá, M. Moško, I. Píš, T. Vojteková, L. Pribusová Slušná, P. Hutár, M. Precner et al.

Molybdenum disulfide is a promising candidate for various applications in electronics, optoelectronics, or alkali-ion batteries. The natural presence of the van der Waals gap allows intercalating alkali ions, such as lithium, into MoS2 films. Intercalation can modify the electronic structure as well as the electrical and optical properties. Here, we present a structural, optical, and electrical characterization of Li-intercalated few-layer MoS2 films. The intercalation was carried out by annealing MoS2 film in the presence of Li2S powder, serving as a lithium source. The initial MoS2 layers were prepared by pulsed laser deposition (PLD) and by sulfurization of 1 nm thick Mo film (TAC). The presence of lithium was confirmed by synchrotron-based x-ray Photoelectron Spectroscopy. The Raman spectroscopy, x-ray diffraction, and optical absorption measurements confirmed semiconducting behavior for all samples. All samples exhibited the thermally activated dependence of the electrical resistance, R, typical for the Efros–Shklovskii variable range hopping in a disordered semiconductor, ln R(T) ∝ (TES/T)1/2, where kBTES is the hopping activation energy. The PLD-grown MoS2 samples exhibited a relatively mild initial disorder primarily caused by grain boundaries. Lithium intercalation led to an increase in disorder, evident in the increase in kBTES and a substantial rise in electrical resistance. The TAC-grown undoped MoS2 sample already exhibited significant resistance, and the impact of Li intercalation on resistance was minimal. This observation was attributed to the fact that the TAC-grown MoS2 samples exhibit a perturbed stoichiometry (the S:Mo ratio ∼ 2.20), causing strong disorder even before Li intercalation. The electron doping caused by lithium, if any, was completely obscured by the effect of disorder.

Pellacani, P.; Jefimovs, K.; Angelini, M.; Marabelli, F.; Tolardo, V.; Kazazis, D.; Floris, F.

The selection of an affordable method to fabricate plasmonic metasurfaces needs to guarantee complex control over both tunability and reproducibility of their spectral and morphological properties, making plasmonic metasurfaces suitable for integration into different sensing devices. Displacement Talbot lithography could be a valid solution thanks to the limited fabrication steps required, also providing the highly desired industrial scalability. Fabricated plasmonic metasurfaces are represented by a gold nanohole array on a glass substrate based on a triangular pattern. Scanning electron microscopy measurements have been recorded, showing the consistency of the surface features with the optimized design parameters. Reflectance and transmittance measurements have also been carried out to test the reliability and standardization of the metasurface’s optical response. Furthermore, these plasmonic metasurfaces have also been successfully tested for probing refractive index variations in a microfluidic system, paving the way for their use in sensitive, real-time, label-free, and multiplexing detection of bio-molecular events.