Topologically protected chiral skyrmion is an intriguing spin texture, which has attracted much attention because of fundamental research and future spintronic applications. MnSi with the non-centrosymmetric structure is well-known material hosting skyrmion phase. To date, preparation of MnSi crystals has been investigated by using special instruments with ultrahigh vacuum chamber. Here, we introduce a facile way to grow MnSi films on sapphire, which is in relatively low vacuum environment of conventional magnetron sputtering. Magnetotransport properties including Hall resistivity measurements allow to confirm the existence of skyrmion phase in MnSi film. Because as-grown MnSi films on sapphire has polycrystalline nature, the emergent features of skyrmion phase are limited and complicated. However, we observed the stable skyrmion phase in a broad range of temperatures and magnetic fields, which is explained by phenomenological scaling analyses of Hall resistivities contribution. Our findings provide not only a general way to prepare the materials possessing skyrmion phase, but also insight into further research to stimulate more degrees of freedom in our inquisitiveness.
Effect of Annealing on Al Diffusion and its Impact on the Properties of Ga$_2$O$_3$ Thin Films Deposited on c-plane Sapphire by RF Sputtering
Instituto de Engenharia de Sistemas e Computadores — Microssistemas e Nanotecnologias (INESC MN)（计算机与系统工程学院—微系统与纳米技术研究所）；Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa（核聚变等离子体研究所，里斯本高等理工学院，里斯本大学）；Departamento de Física, Faculdade de Ciências, Universidade de Lisboa（理学院物理系，里斯本大学）；BioISI—Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa（生物与整合科学研究所，理学院，里斯本大学）；Centro de Química Estrutural, Institute of Molecular Sciences and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa（结构化学中心，分子科学研究所，化学工程系，里斯本高等理工学院，里斯本大学）；Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico（核科学与工程系，里斯本高等理工学院）
This paper reports on the deposition of amorphous and crystalline thin films of Ga2O3 by reactive pulsed direct current magnetron sputtering from a liquid gallium target onto fused (f-) quartz and c plane (c-) sapphire substrates, where the temperature of the substrate is varied from room temperature (RT) to 800°C. The deposition rate (up to 37 nm/min at RT on f-quartz and 5 nm/min at 800°C on c-sapphire) is two to five times higher than the data given in the literature for radio frequency sputtering. Deposited onto unheated substrates, the films are X-ray amorphous. Well-defined X-ray diffrac…
Here, we compare the material quality of AlxIn1-xN layers deposited on Si with different crystallographic orientations, (100) and (111), via radio-frequency (RF) sputtering. To modulate their Al content, the Al RF power was varied from 0 to 225 W, whereas the In RF power and deposition temperature were fixed at 30 W and 300oC, respectively. X-ray diffraction measurements reveal a c-axis-oriented wurtzite structure with no phase separation regardless of the Al content (x = 0-0.50), which increases with the Al power supply. The surface morphology of the AlxIn1-xN layers improves with increasing …
Superconducting Nb3Sn films were fabricated on sapphire and fine grain Nb substrates by magnetron sputtering from a single stoichiometric Nb3Sn target. The structural, morphological and superconducting properties of the films annealed for 24 h at temperatures of 800-1000 °C were investigated. The effect of the annealing time at 1000 °C was examined for 1, 12, and 24 h. The film properties were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. The DC superconducting properties of the films wer…
Gallium oxide films were grown by HVPE on (0001) sapphire substrates with and without $α$-Cr$_2$O$_3$ buffer produced by RF magnetron sputtering. Deposition on bare sapphire substrates resulted in a mixture of $α$-Ga$_2$O$_3$ and $ε$-Ga$_2$O$_3$ phases with a dislocation density of about $2\cdot10^{10}$ cm$^{-2}$. The insertion of $α$-Ga$_2$O$_3$ buffer layers resulted in phase-pure $α$-Ga$_2$O$_3$ films and a fourfold reduction of the dislocation density to $5 \cdot 10^9$ cm$^{-2}$.
The bulk quaternary equiatomic CoCrFeNi alloy is studied extensively in literature. Under experimental conditions, it shows a single-phase fcc structure and its physical and mechanical properties are similar to those of the quinary equiatomic CoCrFeMnNi alloy. Many studies in literature have focused on the mechanical properties of bulk nanocrystalline high entropy alloys or compositionally complex alloys, and their microstructure evolution upon annealing. The thin film processing route offers an excellent alternative to form nanocrystalline alloys. Due to the high nucleation rate and high dens…
Si-doped GaN films were grown on $\textit{c}$-sapphire by rf magnetron reactive co-sputtering of GaAs and Si at various partial pressures of N$_2$ in Ar-N2 growth atmosphere and their epitaxial character was ascertained by phi-scans. Energy dispersive x-ray spectroscopy revealed $\thicksim$2 at.% Si in all the films, but the N/Ga ratio decreased substantially as N$_2$ percentage was reduced from 100% to 10%. High resolution x-ray diffraction revealed the dominant presence of edge dislocations ($\thicksim$10$^{12}$ cm$^{-2}$) in the films grown at 30% - 100% N$_2$, which decreased to $\thicksim…
