ترغب بنشر مسار تعليمي؟ اضغط هنا

Transversal growth microstructures of quasicrystalline Ti-Zr-Ni films

100   0   0.0 ( 0 )
 نشر من قبل Valerie Brien
 تاريخ النشر 2020
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Valerie Brien




اسأل ChatGPT حول البحث

Pulsed laser deposition from a Nd:YAG laser was employed in production of hundreds of nanometer thick quasicrystalline Ti-Zr-Ni films on glass substrate. The influence of deposition temperature Ts on the structure, morphology and microstructure of the films across their thickness was investigated. The morphology and microstructure features were evaluated by X-ray diffraction and transmission electron microscopy techniques. The low deposition temperatures were found to produce films with nanometer sized grains embedded in an amorphous matrix. The grains exhibit quasicrystalline order. The higher deposition temperatures lead to films whose structure is not uniform all along the growth direction. The layer in contact with the substrate is a very thin amorphous layer. The main part of the film consists of crystallized columns. The columns have grown from a nano-crystallized layer where the size of crystallites increases with increasing thickness.



قيم البحث

اقرأ أيضاً

308 - Valerie Brien 2020
The preparation in thin film form of the known icosahedral phase in Ti-Ni-Zr bulk alloys has been investigated as a function of substrate temperature. Films were deposited by Pulsed Laser Deposition on sapphire substrates at temperatures ranging from room temperature to 350$^circ$C. Morphological and structural modifications have been followed by grazing incidence and $theta$-2$theta$ X-ray diffraction, transmission electron diffraction and imaging. Chemical composition has been analysed by Electron Probe Micro-Analysis. The in-depth variation of composition has been studied by Secondary Neutral Mass Spectroscopy. We show that Pulsed Laser Deposition at 275$^circ$C makes the formation of a 1 m thick film of Ti-Ni-Zr quasicrystalline textured nanocrystallites possible.
224 - Gintare Statkute 2015
GaAs nanowires were grown by metalorganic vapor phase epitaxy on evaporated metal films (Au, Au / Pd, Ag, Ni, Ga, Cu, Al, Ti). The samples were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM images reveal that nanowires grow directly on the metals. TEM characterization shows crystalline nanowire (nw) structure originating from Au. Article presents state of the art about nanowire-metal interface growth and enumerates nanowire contacting methods with metals.
We report on the synthesis of carbon nanotubes on quasicrystalline alloys. Aligned multiwalled carbon nanotubes (MWNTs) on the conducting faces of decagonal quasicrystals were synthesized using floating catalyst chemical vapor deposition. The alignme nt of the nanotubes was found perpendicular to the decagonal faces of the quasicrystals. A comparison between the growth and tube quality has also been made between tubes grown on various quasicrystalline and SiO2 substrates. While a significant MWNT growth was observed on decagonal quasicrystalline substrate, there was no significant growth observed on icosahedral quasicrystalline substrate. Raman spectroscopy and high resolution transmission electron microscopy (HRTEM) results show high crystalline nature of the nanotubes. Presence of continuous iron filled core in the nanotubes grown on these substrates was also observed, which is typically not seen in MWNTs grown using similar process on silicon and/or silicon dioxide substrates. The study has important implications for understanding the growth mechanism of MWNTs on conducting substrates which have potential applications as heat sinks.
Among the recent discoveries of domain wall functionalities, the observation of electrical conduction at ferroelectric domain walls in the multiferroic insulator BiFeO3 has opened exciting new possibilities. Here, we report evidence of electrical con duction also at 180{deg} ferroelectric domain walls in the simpler tetragonal ferroelectric PZT thin films. The observed conduction shows nonlinear, asymmetric current-voltage characteristics, thermal activation at high temperatures and high stability. We relate this behavior to the microscopic structure of the domain walls, allowing local defects segregation, and the highly asymmetric nature of the electrodes in our local probe measurements.
An interaction potential energy between and adsorbate (Xe and Ar) and the 10-fold Al-Ni-Co quasicrystal is computed by summing over all adsorbate-substrate interatomic interactions. The quasicrystal atoms coordinates are obtained from LEED experiment s and the Lennard-Jones parameters of Xe-Al, Xe-Ni and Xe-Co are found using semiempirical combining rules. The resulting potential energy function of position is highly corrugated. Monolayer adsorption of Xe and Ar on the quasicrystal surface is investigated in two cases: 1) in the limit of low coverage (Henrys law regime), and 2) at somewhat larger coverage, when interactions between adatoms are considered through the second virial coefficient, C_{AAS}. A comparison with adsorption on a flat surface indicates that the corrugation enhances the effect on Xe-Xe (Ar-Ar) interactions. The theoretical results for the low coverage adsorption regime are compared to experimental (LEED isobar) data.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا