In situ and Ex situ Measurements of Stress Evolution in the Cobalt-Silicon System

2000 ◽  
Vol 611 ◽  
Author(s):  
G. Lucadamo ◽  
C. Lavoie ◽  
C. Cabral ◽  
R. A. Carruthers ◽  
J.M.E. Harper
Keyword(s):  
Room Temperature ◽  
Biaxial Stress ◽  
Ex Situ ◽  
Silicide Formation ◽  
Stress Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bending Force ◽  
Constant Heating

ABSTRACTThe biaxial stress in Co thin-films has been investigated in situ by measuring changes in substrate curvature that occurred during deposition and annealing.Films of Co, 35 to 500 nm in thickness, were deposited by UHV magnetron sputtering at room temperature on Si (100) and poly-Si substrates.Results show that during Co deposition the bending force increased linearly with film thickness; a signature of constant stress.In addition, the stress evolution during silicide formation was measured under constant heating rate conditions from room temperature up to 700°C. The stress-temperature curve was correlated with Co2Si, CoSi, and CoSi2 phase formation using in situ synchrotron X-ray diffraction measurements.The room temperature stress for the CoSi2 phase was found to be ∼0.8 GPa (tensile) in the films deposited on Si (100) and ∼1 GPa (tensile) on the films deposited on poly-Si.The higher tensile stress in the poly-Si sample could be a result of Si grain growth during annealing.

scholarly journals Epitaxial growth and structure of cobalt ferrite thin films with large inversion parameter on Ag(001)

2019 ◽  
Vol 75 (1) ◽  
pp. 8-17 ◽  
Author(s):  
Maurizio De Santis ◽  
Aude Bailly ◽  
Ian Coates ◽  
Stéphane Grenier ◽  
Olivier Heckmann ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Structure ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Octahedral Sites

Cobalt ferrite ultrathin films with the inverse spinel structure are among the best candidates for spin filtering at room temperature. High-quality epitaxial CoFe2O4 films about 4 nm thick have been fabricated on Ag(001) following a three-step method: an ultrathin metallic CoFe2 alloy was first grown in coherent epitaxy on the substrate and then treated twice with O2, first at room temperature and then during annealing. The epitaxial orientation and the surface, interface and film structure were resolved using a combination of low-energy electron diffraction, scanning tunnelling microscopy, Auger electron spectroscopy and in situ grazing-incidence X-ray diffraction. A slight tetragonal distortion was observed, which should drive the easy magnetization axis in-plane due to the large magneto-elastic coupling of such a material. The so-called inversion parameter, i.e. the Co fraction occupying octahedral sites in the ferrite spinel structure, is a key element for its spin-dependent electronic gap. It was obtained through in situ resonant X-ray diffraction measurements collected at both the Co and Fe K edges. The data analysis was performed using FDMNES, an ab initio program already extensively used to simulate X-ray absorption spectroscopy, and shows that the Co ions are predominantly located on octahedral sites with an inversion parameter of 0.88 (5). Ex situ X-ray photoelectron spectroscopy gives an estimation in accordance with the values obtained through diffraction analysis.

Amorphization of nanocrystalline 3C-SiC irradiated with Si+ ions

2010 ◽  
Vol 25 (12) ◽  
pp. 2341-2348 ◽  
Author(s):  
W. Jiang ◽  
H. Wang ◽  
I. Kim ◽  
Y. Zhang ◽  
W.J. Weber
Keyword(s):  
Grain Size ◽  
Single Crystal ◽  
Room Temperature ◽  
Ex Situ ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Channeling

Irradiation-induced amorphization in nanocrystalline and single-crystal 3C-SiC has been studied using 1 MeV Si+ ions under identical irradiation conditions at room temperature and 400 K. The disordering behavior has been characterized using in situ ion channeling and ex situ x-ray diffraction methods. The results show that, compared with single-crystal 3C-SiC, full amorphization of small 3C-SiC grains (˜3.8 nm in size) at room temperature occurs at a slightly lower dose. Grain size decreases with increasing dose until a fully amorphized state is attained. The amorphization dose increases at 400 K relative to room temperature. However, at 400 K, the amorphization dose for 2.0 nm grains is about a factor of 4 and 8 smaller than for 3.0 nm grains and bulk single-crystal 3C-SiC, respectively. The behavior is attributed to the preferential amorphization at the interface.

Stress Evolution in Thin Films; Diffusion and Reactions

2007 ◽  
Vol 264 ◽  
pp. 71-78 ◽  
Author(s):  
U. Welzel ◽  
Eric J. Mittemeijer
Keyword(s):  
Phase Formation ◽  
Ex Situ ◽  
Microstructural Development ◽  
Diffusion Annealing ◽  
Stress Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Film Diffusion ◽  
Compressive Residual Stresses

After a brief discussion of possible mechanisms of stress generation in thin film diffusion/reaction couples, two recent experimental examples are reviewed: (i) Thin film diffusion couples (Pd-Cu, individual layer thicknesses: 50nm) prepared by DC-magnetron sputtering on silicon substrates. The microstructural development, phase formation and the stress evolution during diffusion annealing have been investigated employing Auger-electron spectroscopy in combination with sputter depth profiling, transmission electron microscopy, in-situ wafer-curvature measurements and ex-situ and, in particular, in-situ X-ray diffraction measurements. (ii) Tin layers on copper substrates (layer thicknesses of some microns) prepared by electrodeposition. Upon storage at ambient temperatures, Cu diffuses into the Sn layer and forms the intermetallic phase η’- Cu6Sn5. The phase formation is accompanied by a volume expansion and as a consequence, compressive residual stresses can be generated in the Sn layers. These compressive residual stresses may drive the formation of Sn whiskers on the Sn surface. The microstructural development, phase formation and the stress evolution during diffusion annealing have been investigated employing scanning electron and focused ion beam microscopy, metallography and ex-situ and, in particular, in-situ X-ray diffraction measurements.

In Situ X-Ray Diffraction Investigations during Diffusion Anneals of Ni-Cu Thin Film Diffusion Couples

2010 ◽  
Vol 89-91 ◽  
pp. 503-508 ◽  
Author(s):  
J. Sheng ◽  
U. Welzel ◽  
Eric J. Mittemeijer
Keyword(s):  
Thermal Stresses ◽  
Stress Generation ◽  
Ex Situ ◽  
Diffusion Annealing ◽  
X Ray Diffraction ◽  
Individual Layer ◽  
X Ray ◽  
Bilayer System ◽  
Stress Changes

The stress evolution during diffusion annealing of Ni-Cu bilayers (individual layer thicknesses of 50 nm) was investigated employing ex-situ and in-situ X-ray diffraction measurements. Annealing at relatively low homologous temperatures (about 0.3 - 0.4 Tm) for durations up to about 100 hours results in considerable diffusional intermixing, as demonstrated by Auger-electron spectroscopy investigations (in combination with sputter-depth profiling). In addition to thermal stresses due to differences of the coefficients of thermal expansion of layers and substrate, tensile stress con-tributions in the sublayers arise during the diffusion anneals. The obtained stress data have been discussed in terms of possible mechanisms of stress generation. The influence of diffusion on stress development in the sublayers of the diffusion couple during heating and isothermal annealing was investigated by comparing stress changes in the bilayer system with corresponding results obtained under identical conditions for single layers of the components in the bilayer system. The specific residual stresses that emerge due to diffusion between the (sub)layers in the bilayer could thereby be identified.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

In Situ Synchrotron X-Ray Diffraction Study of a Deformed Cu-Fe-P Alloy during Heating

2016 ◽  
Vol 850 ◽  
pp. 191-196 ◽  
Author(s):  
Wei Wang ◽  
Cun Lei Zou ◽  
Ren Geng Li ◽  
Wen Wen ◽  
Hui Jun Kang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lattice Distortion ◽  
Copper Matrix ◽  
Heating Process ◽  
Recrystallization Process ◽  
Full Width ◽  
X Ray Diffraction ◽  
Dramatic Decrease ◽  
X Ray

In situ synchrotron X-ray diffraction was used to study a deformed Cu-0.88 Fe-0.24 P alloy during heating process. The measurements were performed at room temperature and also at high temperatures up to 893 K in order to determine the recovery, ageing and recrystallization process. With the increase of temperature, the angles of copper matrix peaks moved left and the FWHM (full width at half maximum) decreased slightly. Fe3P precipitates were first detected at 533 K, reached the maximum at 673 K, and re-dissolved into matrix at 853 K. A dramatic decrease in FWHM was observed accompanied by the precipitation of Fe3P phases, indicating the reduction of lattice distortion of copper matrix.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

scholarly journals A study on preparation and characterization of carbon doped TiO2 nanotubes

2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Srimala Sreekantan ◽  
Roshasnorlyza Hazan ◽  
Zainovia Lockman ◽  
Ishak Mat
Keyword(s):  
Methyl Orange ◽  
Tio2 Nanotubes ◽  
Pure Tio2 ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Methyl Orange Degradation ◽  
Doped Tio2 ◽  
X Ray ◽  
Carbon Doped

The present study is directed to clarify the influence of carbon doping on the degradation of methyl orange. TiO2 nanotubes were prepared by anodizing titanium foils in a two electrode configuration bath with titanium foil as the anode and platinum as the counter electrode. The electrochemical bathconsists of 1 M Na2SO4 with 0.7 g ammonium fluoride, NH4F. The nanotubes obtained were further doped with carbon via in-situ and ex-situ method. Incorporation of carbon on TiO2 via in-situ method is accomplished during the anodization process by introducing oxalic acid into electrolyte while theex-situ doping involves carbon incorporation into pre-fabricated TiO2 nanotube via flame annealing using carbon blackN330. Characterization such as Scanning Electron Microscope (SEM), Energy Dispersive X-ray Analysis (EDX), and X-Ray Diffraction (XRD) are used to determine the surfacemorphology, composition of dopants, and phases exists. Well ordered nanotube with good adherence and smooth surface was obtained for both methods. When the oxide was annealed, X-ray diffraction analysis revealed the presence of anatase and rutile phase. The photocatalytic properties of thepure TiO2 and carbon doped TiO2 were tested for methyl orange degradation and the result indicated that the in-situ doped TiO2 has much better degradation than the ex-situ and pure TiO2. The percentage of methyl orange degradation for in-situ was 20% and 41% higher than ex-situ doped TiO2 and pure TiO2, respectively.

Sign in / Sign up

Export Citation Format

Share Document