Transparent conducting thin films were deposited on quartz substrates using radio frequency (rf) magnetron sputtering at 20% oxygen partial pressure. In the visible region, the transmittance of Zn-doped thin films is relatively low, whereas the thin film has a high transmittance of about 80%. The electrical conductivity increases rapidly with the increase in doping concentration. At room temperature, the electrical conductivity for the doped sample with is , which is about 2 orders of magnitude higher than that of the undoped sample . In the temperature range of , the temperature dependence of the conductivity for thin films is of semiconducting thermal-activation type. These results indicate that it is possible to improve the conductivity of thin film by Zn doping with the help of controlling the oxygen deficiency.
Abstract The structural features and the electron energy loss spectrum of black phosphorus (BP) have been experimentally analyzed and they are discussed based on a theoretical calculation. The low-energy loss spectra of typical samples reveal that the emerging high-mobility two-dimensional material BP often exhibits both bulk and surface plasmon modes. The surface modes of BP are strongly thickness dependent. Electrodynamic analysis indicates that the Fuchs–Kliewer-like surface plasmon modes consist of two branches with different charge symmetry: the upper side and lower side have the same charge polarity as the lower branch and the opposite charge polarity to the upper branch. This study provides fundamental insight into the characteristic nature of BP plasmonics.
The photoinduced martensitic (MT) transition and reverse transition in a shape memory alloy $\mathrm{M}{\mathrm{n}}_{50}\mathrm{N}{\mathrm{i}}_{40}\mathrm{S}{\mathrm{n}}_{10}$ have been examined by using high spatiotemporal resolution four-dimensional transmission electron microscopy (4D-TEM), and the experimental results clearly demonstrate that the MT transition and reverse transition in this Heusler alloy contain a variety of structural dynamic features at picosecond time scales. The 4D-TEM imaging and diffraction observations clearly show that MT transition and MT domain nucleation, which are related to cooperative atomic motions, occur at between 10 and 20 ps, depending on the thickness of the sample. Moreover, a strong coupling between the MT transition and lattice breathing mode is discovered in this system, which can result in a periodic structural oscillation between the MT phase and austenitic (AUS) phase. This allows us to directly observe the MT nucleation and domain wall motions in transient states using high spatiotemporal imaging. A careful analysis of the ultrafast images demonstrates the presence of remarkable transient states, which exhibit the essential features of MT nucleation, lattice symmetry breaking, and a rapid growth of MT plates. These results not only provide insights into the time-resolved structural dynamics and elementary mechanisms that govern the MT transition but also contribute to the development of a novel technique for future 4D-TEM investigations.
We investigated the martensitic transition and the magnetic properties of Mn 1-x CoGe melt-spun ribbons. The as-prepared Mn 1-x CoGe ribbons crystallize in austenite hexagonal phase with a textured structure. The postannealing process promotes the formation of the martensitic phase and homogenization of the alloy, resulting in a first-order magnetostructural transition in the annealed ribbons, and thus a giant magnetocaloric effect. The magnetic entropy change around the transition reaches 19 J/kgK for a magnetic field change of 0-5 T. Furthermore, it is found that the hysteresis loss around the magnetostructural transition is negligible in present annealed ribbons, which would facilitate the application of Mn 1-x CoGe alloys.
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