Charge transfer in binary alloys: A future for electron energy loss spectroscopy in materials science

1988 ◽  
Vol 46 ◽  
pp. 2-5
Author(s):  
C. C. Ahn ◽  
D. H. Pearson ◽  
B. T. Fultz
Keyword(s):  
Charge Transfer ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Bound States ◽  
Binary Alloys ◽  
Threshold Energy ◽  
Enthalpies Of Formation ◽  
White Line ◽  
Electron Energy Loss

The redistribution of atomic charge which takes place from an atom of one type to that of another in a binary alloy system is fundamental to the formulation of models of enthalpies of formation of these systems. Of special interest are charge transfers where one of the alloy constituents is from the first row transition series. The extent to which the 3d band is filled, ultimately plays an important role in the propensity with which alloys will form intermetallic phases. An understanding of electron charge transfer is important not only in crystalline systems but can also serve as the basis for the determination of the extent of chemical short range order (CSRO) in amorphous binary alloys.Electron energy loss spectroscopy (EELS) in the electron microscope can probe unoccupied bound states and unlike other spectroscopies which probe core levels, is not surface sensitive. The features of the energy loss spectra of the 3d metals which make charge transfer studies possible are the L23 transitions. These spectra are characterized by two “white lines” at the threshold energy which result from ionizations from the 2p3/2 and 2p1/2 spin orbit subshells to a narrow bound 3d state. Beneath and beyond the white line transitions are transitions to the continuum states.

The Change of D-Electron Occupancy in TiNi and Ni3Ti Compounds Measured from the White-Line Intensity of Electron Energy Loss Spectroscopy

2012 ◽  
Vol 538-541 ◽  
pp. 2350-2353
Author(s):  
Wei Guo Yang
Keyword(s):  
Charge Transfer ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Line Intensity ◽  
White Line ◽  
Charge Neutrality ◽  
Charge Transfer Mechanism ◽  
Local Charge ◽  
Electron Energy Loss

The electron energy loss spectroscopy (EELS) of pure Ti, TiNi, Ni3Ti and pure Ni has been acquired and d-electron occupancy of both Ti and Ni in the metals has been measured from the white-line intensity. It is found that the change of d-electron occupancy of Ni is very small in all metals, but the d-electron occupancy of Ti in Ni3Ti increases considerable large relative to pure Ti. The change of d-electron occupancy is discussed in terms of charge transfer mechanism, local charge neutrality (LCN) approximation, and hybridization.

The Measured Change in d-Electron of Ni in Ni-7.2at%Ti Alloy Studied by Electron Energy Loss Spectroscopy

2014 ◽  
Vol 887-888 ◽  
pp. 370-373
Author(s):  
Wei Guo Yang
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Line Intensity ◽  
Ti Alloy ◽  
White Line ◽  
Measured Change ◽  
Electron Energy Loss

A Ni-7.2at%Ti alloy was prepared and thed-electron occupancy of Ni was measured from electron energy loss spectroscopy (EELS) of nickel. The results showed that the white-line intensity of Ni EELS and thed-electron occupancy of Ni in Ni-7.2at%Ti alloy did not change significantly relative to pure Ni.

Fast Mapping of the Cobalt-Valence State in Ba0.5Sr0.5Co0.8Fe0.2O3-dby Electron Energy Loss Spectroscopy

2013 ◽  
Vol 19 (6) ◽  
pp. 1595-1605 ◽  
Author(s):  
Philipp Müller ◽  
Matthias Meffert ◽  
Heike Störmer ◽  
Dagmar Gerthsen
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence State ◽  
Hexagonal Phase ◽  
Fast Method ◽  
White Line ◽  
Valence States ◽  
Electron Energy Loss

AbstractA fast method for determination of the Co-valence state by electron energy loss spectroscopy in a transmission electron microscope is presented. We suggest the distance between the Co-L3and Co-L2white-lines as a reliable property for the determination of Co-valence states between 2+ and 3+. The determination of the Co-L2,3white-line distance can be automated and is therefore well suited for the evaluation of large data sets that are collected for line scans and mappings. Data with a low signal-to-noise due to short acquisition times can be processed by applying principal component analysis. The new technique was applied to study the Co-valence state of Ba0.5Sr0.5Co0.8Fe0.2O3-d(BSCF), which is hampered by the superposition of the Ba-M4,5white-lines on the Co-L2,3white-lines. The Co-valence state of the cubic BSCF phase was determined to be 2.2+ (±0.2) after annealing for 100 h at 650°C, compared to an increased valence state of 2.8+ (±0.2) for the hexagonal phase. These results support models that correlate the instability of the cubic BSCF phase with an increased Co-valence state at temperatures below 840°C.

The Influence of Ti on d-Electron Occupancy of Fe in Fe-1.7%Ti Alloy

2013 ◽  
Vol 395-396 ◽  
pp. 259-261
Author(s):  
Wei Guo Yang ◽  
De Hui Li ◽  
Hong Jin Cai ◽  
Xin Cai ◽  
Huan Chen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Line Intensity ◽  
Pure Iron ◽  
Ti Alloy ◽  
White Line ◽  
Electron Energy Loss

An Fe-1.7wt% Ti alloy was prepared and the electron energy loss spectroscopy (EELS) of iron was collected. Thed-electron occupancy of Fe is measured from the white-line intensity of EELS. It was found that relative to pure iron thed-electron occupancy of Fe in Fe-1.7wt% Ti alloy increased.

The Change of L Edge of Electron Energy Loss Spectroscopy of Ni in Ni-Based Solid-Solution Alloys

2012 ◽  
Vol 548 ◽  
pp. 221-224
Author(s):  
W.G. Yang ◽  
Y. Cheng
Keyword(s):  
Solid Solution ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Line Intensity ◽  
White Line ◽  
Electron Energy Loss

The electron energy loss spectroscopy (EELS) of Ni in a series of Ni-based solid-solution alloys and pure Ni has been collected. It is found that the distance between L2 and L3 peaks of Ni EELS is enlarged in all alloys relative to pure Ni. The d-electron occupancy of Ni in all alloys is measured from the white-line intensity of EELS and the results vary very small.

The Study of Electron Energy Loss Spectroscopy of Ni-4.8at%Ti Alloy

2013 ◽  
Vol 446-447 ◽  
pp. 8-11
Author(s):  
Wei Guo Yang ◽  
De Hui Li ◽  
Hong Jin Cai ◽  
Xin Cai ◽  
Huan Chen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Line Intensity ◽  
Ti Alloy ◽  
White Line ◽  
Electron Energy Loss

An Ni-4.8at%Ti alloy was prepared and the electron energy loss spectroscopy (EELS) of nickel was collected. Thed-electron occupancy of Ni is measured from the white-line intensity of EELS. It was found that relative to pure Ni thed-electron occupancy of Ni in Ni-4.8at%Ti alloy did not change significantly.

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