scholarly journals Stress-Induced In Situ Modification of Transition Temperature in VO2 Films Capped by Chalcogenide

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5541
Author(s):  
Joe Sakai ◽  
Masashi Kuwahara ◽  
Kunio Okimura ◽  
Yoichi Uehara
Keyword(s):  
Transition Temperature ◽  
Phase Change ◽  
Crystalline Phase ◽  
Structural Phase ◽  
Rf Magnetron Sputtering ◽  
Significant Drop ◽  
In Situ Modification ◽  
Diffusion Barrier Layer ◽  
Chalcogenide Layer

We attempted to modify the monoclinic–rutile structural phase transition temperature (Ttr) of a VO2 thin film in situ through stress caused by amorphous–crystalline phase change of a chalcogenide layer on it. VO2 films on C- or R-plane Al2O3 substrates were capped by Ge2Sb2Te5 (GST) films by means of rf magnetron sputtering. Ttr of the VO2 layer was evaluated through temperature-controlled measurements of optical reflection intensity and electrical resistance. Crystallization of the GST capping layer was accompanied by a significant drop in Ttr of the VO2 layer underneath, either with or without a SiNx diffusion barrier layer between the two. The shift of Ttr was by ~30 °C for a GST/VO2 bilayered sample with thicknesses of 200/30 nm, and was by ~6 °C for a GST/SiNx/VO2 trilayered sample of 200/10/6 nm. The lowering of Ttr was most probably caused by the volume reduction in GST during the amorphous–crystalline phase change. The stress-induced in in situ modification of Ttr in VO2 films could pave the way for the application of nonvolatile changes of optical properties in optoelectronic devices.

In situ study of vacancy disordering in crystalline phase-change materials under electron beam irradiation

2020 ◽  
Vol 187 ◽  
pp. 103-111 ◽  
Author(s):  
Ting-Ting Jiang ◽  
Xu-Dong Wang ◽  
Jiang-Jing Wang ◽  
Yu-Xing Zhou ◽  
Dan-Li Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Phase Change ◽  
Crystalline Phase ◽  
Electron Beam Irradiation ◽  
Phase Change Materials ◽  
Beam Irradiation ◽  
In Situ Study

scholarly journals In-situ TEM Investigation of the Amorphous to Crystalline Phase Change During Electrical Breakdown of Highly Conductive Polymers at the Atomic Scale

2020 ◽  
Vol 26 (S2) ◽  
pp. 3198-3200
Author(s):  
Michele Conroy ◽  
Kalani Moore ◽  
Rob Lehane ◽  
Alonso Gamero-Quijano ◽  
Micheal Scanlon ◽  
...  
Keyword(s):  
Phase Change ◽  
Crystalline Phase ◽  
Conductive Polymers ◽  
Electrical Breakdown ◽  
Atomic Scale ◽  
In Situ Tem

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

In-situ Modification of Graphene Oxide by Insoluble Sulfur and Application for Nitrile Butadiene Rubber

2020 ◽  
Vol 35 (2) ◽  
pp. 221-228
Author(s):  
S.-B. Chen ◽  
T.-X. Li ◽  
S.-H. Wan ◽  
X. Huang ◽  
S.-W. Cai ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
In Situ Modification

scholarly journals Seawater Absorption and Adhesion Properties of Hydrophobic and Superhydrophobic Thermoset Epoxy Nanocomposite Coatings

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Salt Spray ◽  
Adhesion Properties ◽  
In Situ Modification ◽  
Long Time ◽  
Seawater Environment ◽  
Thermoset Epoxy ◽  
The Cost

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.

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