scholarly journals Structural Evolution of MoO3 Thin Films Deposited on Copper Substrates upon Annealing: An X-ray Absorption Spectroscopy Study

2019 ◽  
Vol 4 (2) ◽  
pp. 41 ◽  
Author(s):  
Macis ◽  
Rezvani ◽  
Davoli ◽  
Cibin ◽  
Spataro ◽  
...  
Keyword(s):  
Thin Films ◽  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Structural Evolution ◽  
Ex Situ ◽  
Edge Structure ◽  
X Ray ◽  
High Gradients ◽  
Different Temperatures ◽  
X Ray Absorption

Structural changes of MoO3 thin films deposited on thick copper substrates upon annealing at different temperatures were investigated via ex situ X-Ray Absorption Spectroscopy (XAS). From the analysis of the X-ray Absorption Near-Edge Structure (XANES) pre-edge and Extended X-ray Absorption Fine Structure (EXAFS), we show the dynamics of the structural order and of the valence state. As-deposited films were mainly disordered, and ordering phenomena did not occur for annealing temperatures up to 300 °C. At ~350 °C, a dominant α-MoO3 crystalline phase started to emerge, and XAS spectra ruled out the formation of a molybdenum dioxide phase. A further increase of the annealing temperature to ~500 °C resulted in a complex phase transformation with a concurrent reduction of Mo6+ ions to Mo4+. These original results suggest the possibility of using MoO3 as a hard, protective, transparent, and conductive material in different technologies, such as accelerating copper-based devices, to reduce damage at high gradients.

Operando X-ray absorption spectroscopy study of the Fischer–Tropsch reaction with a Co catalyst

2019 ◽  
Vol 26 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Chandrani Nayak ◽  
Preeti Jain ◽  
C. P. Vinod ◽  
S. N. Jha ◽  
D. Bhattacharyya
Keyword(s):  
Absorption Spectroscopy ◽  
Catalytic Reaction ◽  
Structural Changes ◽  
Ambient Pressure ◽  
Metallic Phase ◽  
Fischer Tropsch ◽  
Co Catalyst ◽  
X Ray ◽  
Different Temperatures ◽  
X Ray Absorption

This article describes the setting up of a facility on the energy-scanning EXAFS beamline (BL-09) at RRCAT, Indore, India, for operando studies of structure–activity correlation during a catalytic reaction. The setup was tested by operando X-ray absorption spectroscopy (XAS) studies performed on a Co-based catalyst during the Fischer–Tropsch reaction to obtain information regarding structural changes in the catalyst during the reaction. Simultaneous gas chromatography (GC) measurements during the reaction facilitate monitoring of the product gases, which in turn gives information regarding the activity of the catalyst. The combination of XAS and GC techniques was used to correlate the structural changes with the activity of the catalyst at different reaction temperatures. The oxide catalyst was reduced to the metallic phase by heating at 400°C for 5 h under H2 at ambient pressure and subsequently the catalytic reaction was studied at four different temperatures of 240, 260, 280 and 320°C. The catalyst was studied for 10 h at 320°C and an attempt has been made to understand the process of its deactivation from the XANES and EXAFS results.

scholarly journals X-ray absorption spectroscopy elucidates the impact of structural disorder on electron mobility in amorphous zinc-tin-oxide thin films

2014 ◽  
Vol 104 (24) ◽  
pp. 242113 ◽  
Author(s):  
Sin Cheng Siah ◽  
Sang Woon Lee ◽  
Yun Seog Lee ◽  
Jaeyeong Heo ◽  
Tomohiro Shibata ◽  
...  
Keyword(s):  
Thin Films ◽  
Absorption Spectroscopy ◽  
Tin Oxide ◽  
Electron Mobility ◽  
Structural Disorder ◽  
Oxide Thin Films ◽  
X Ray ◽  
Zinc Tin Oxide ◽  
The Impact ◽  
X Ray Absorption

scholarly journals Structural Evolution in Wet Mechanically Alloyed Co-Fe-(Ta,W)-B Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 800
Author(s):  
Vladimír Girman ◽  
Maksym Lisnichuk ◽  
Daria Yudina ◽  
Miloš Matvija ◽  
Pavol Sovák ◽  
...  
Keyword(s):  
Structural Changes ◽  
Magnetic Measurements ◽  
Structural Evolution ◽  
High Energy ◽  
Control Agent ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron ◽  
X Ray Absorption

In the present study, the effect of wet mechanical alloying (MA) on the glass-forming ability (GFA) of Co43Fe20X5.5B31.5 (X = Ta, W) alloys was studied. The structural evolution during MA was investigated using high-energy X-ray diffraction, X-ray absorption spectroscopy, high-resolution transmission electron microscopy and magnetic measurements. Pair distribution function and extended X-ray absorption fine structure spectroscopy were used to characterize local atomic structure at various stages of MA. Besides structural changes, the magnetic properties of both compositions were investigated employing a vibrating sample magnetometer and thermomagnetic measurements. It was shown that using hexane as a process control agent during wet MA resulted in the formation of fully amorphous Co-Fe-Ta-B powder material at a shorter milling time (100 h) as compared to dry MA. It has also been shown that substituting Ta with W effectively suppresses GFA. After 100 h of MA of Co-Fe-W-B mixture, a nanocomposite material consisting of amorphous and nanocrystalline bcc-W phase was synthesized.

X-ray Absorption Spectroscopy Study of TiO2–x Thin Films for Memory Applications

2015 ◽  
Vol 119 (8) ◽  
pp. 4362-4370 ◽  
Author(s):  
D. Carta ◽  
G. Mountjoy ◽  
A. Regoutz ◽  
A. Khiat ◽  
A. Serb ◽  
...  
Keyword(s):  
Thin Films ◽  
Absorption Spectroscopy ◽  
Spectroscopy Study ◽  
X Ray ◽  
Memory Applications ◽  
X Ray Absorption

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.

Ascertaining the nanocluster formation within an ion-irradiated Pt/Ni/C multi-trilayer with X-ray absorption spectroscopy

2012 ◽  
Vol 20 (1) ◽  
pp. 137-144
Author(s):  
Nitya Ramanan ◽  
Sumalay Roy ◽  
Debdutta Lahiri ◽  
Surinder M. Sharma ◽  
B. N. Dev
Keyword(s):  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Nearest Neighbor ◽  
Ion Irradiation ◽  
Physical Adsorption ◽  
X Ray ◽  
Bimetallic Nanoclusters ◽  
Wave Technique ◽  
Wide Scale ◽  
X Ray Absorption

In this work nanoclusters formed in a Pt/Ni/C multi-trilayer by the ion-irradiated method of synthesis are characterized. In particular, an attempt to understand the role of interfaces in the synthesis is made. With this objective, ion-irradiation-induced structural changes in a Pt/Ni/C multi-trilayer using X-ray absorption spectroscopy (at the NiK-edge) in conjunction with the X-ray standing-wave technique are investigated. The XANES analysis identifies chemical binding at pristine Ni/C and Ni/Pt interfaces, in contrast with physical adsorption at the Pt/C interface. The chemical nature of the interfaces determines their relative stability with respect to irradiation and controls the extent of metallic diffusion. The most interesting structural change, upon irradiation, is the disruption of the Pt/C interface and subsequent migration of Pt atoms towards pre-diffused Ni atoms within the C layer, leading to the formation of Ni-centered Ni–Pt bimetallic nanoclusters (with Ni:Pt = 60:40). These clusters are highly disordered beyond their nearest neighbor and find wide-scale applications as, for example, magnetic devicesetc. The implications of these findings on the design goals are discussed.

X-ray absorption spectroscopy and density functional analysis of the Fe3+ distribution profile on Al sites in a chrysoberyl crystal, BeAl2O4:Fe3+

2016 ◽  
Vol 49 (2) ◽  
pp. 385-388 ◽  
Author(s):  
Kanokwan Kanchiang ◽  
Atipong Bootchanont ◽  
Janyaporn Witthayarat ◽  
Sittichain Pramchu ◽  
Panjawan Thanasuthipitak ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Distribution Profile ◽  
Laser Applications ◽  
Edge Structure ◽  
X Ray ◽  
Site Distribution ◽  
X Ray Absorption

Chrysoberyl is one of the most interesting minerals for laser applications, widely used for medical purposes, as it exhibits higher laser performance than other materials. Although its utilization has been vastly expanded, the location of transition metal impurities, especially the iron that is responsible for chrysoberyl's special optical properties, is not completely understood. The full understanding and control of these optical properties necessitates knowledge of the precise location of the transition metals inside the structure. Therefore, synchrotron X-ray absorption spectroscopy (XAS), a local structural probe sensitive to the different local geometries, was employed in this work to determine the site occupation of the Fe3+ cation in the chrysoberyl structure. An Fe K-edge X-ray absorption near-edge structure (XANES) simulation was performed in combination with density functional theory calculations of Fe3+ cations located at different locations in the chrysoberyl structure. The simulated spectra were then qualitatively compared with the measured XANES features. The comparison indicates that Fe3+ is substituted on the two different Al2+ octahedral sites with the proportion 60% on the inversion site and 40% on the reflection site. The accurate site distribution of Fe3+ obtained from this work provides useful information on the doping process for improving the efficiency of chrysoberyl as a solid-state laser material.

A practical method for determining film thickness using X-ray absorption spectroscopy in total electron yield mode

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Noritake Isomura ◽  
Keiichiro Oh-ishi ◽  
Naoko Takahashi ◽  
Satoru Kosaka
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Absorption Spectroscopy ◽  
Electron Spectroscopy ◽  
Practical Method ◽  
Decay Length ◽  
Total Electron ◽  
X Ray ◽  
Logarithmic Equation ◽  
X Ray Absorption

Thin films formed on surfaces have a large impact on the properties of materials and devices. In this study, a method is proposed using X-ray absorption spectroscopy to derive the film thickness of a thin film formed on a substrate using the spectral separation and logarithmic equation, which is a modified version of the formula used in electron spectroscopy. In the equation, the decay length in X-ray absorption spectroscopy is longer than in electron spectroscopy due to a cascade of inelastic scattering of electrons generated in a solid. The modification factor, representing a multiple of the decay length, was experimentally determined using oxidized Si and Cu with films of thickness 19 nm and 39 nm, respectively. The validity of the proposed method was verified, and the results indicated that the method can be used in the analysis of various materials with thin films.

Sign in / Sign up

Export Citation Format

Share Document