Electrical Characterization of the Structure and Other Phenomena in Superionic PbSnF4

1995 ◽  
Vol 411 ◽  
Author(s):  
Galina Milova ◽  
Georges Denes ◽  
M. Cecilia Madamba ◽  
M. Perfiliev
Keyword(s):  
Ion Mobility ◽  
Complex Impedance ◽  
Electrical Characterization ◽  
Fold Increase ◽  
Fluoride Ion ◽  
Fluoride Ions ◽  
Covalently Bonded ◽  
Frenkel Defects ◽  
Fluorite Type

ABSTRACTThe structure of PbSnF4 is derived from that of fluorite-type β-PbF2 The replacement of half the lead by tin results in a thousand-fold increase of the fluoride ion mobility, even though tin-fluorine bonds are strongly covalent. This is due to an increase of fluoride ion disorder on some sites. The structure of α-PbSnF4 can be interpreted as resulting from the insertion of two layers of [SnF]+ cations between each pair of layers of PbF8 cubes. This has profound bearings on the texture and properties of this material, since the tin(II) stereoactive lone pairs create very effective cleavage planes. In addition, the fluorine covalently bonded to tin occupy all vacant sites used to create Frenkel defects. However, superionicity is observed by complex impedance measurements. Transport number measurements show that fluoride ions are the charge carriers.

Ionic Conductivity of the new Fluoride-Ion Conductor Casn2F6

2002 ◽  
Vol 756 ◽  
Author(s):  
Michael F. Bell ◽  
Georges DéNés ◽  
Zhimeng Zhu
Keyword(s):  
Solid Solution ◽  
Complex Impedance ◽  
Crystalline Material ◽  
Mixed Conductor ◽  
Impedance Method ◽  
Fluoride Ion ◽  
Ion Conductor ◽  
Covalently Bonded ◽  
Fluorite Type ◽  
First Time

ABSTRACTMetastable CaSn2F6 has been prepared for the first time and characterized. It is a well crystalline material that leaches SnF2 in water to give the microcrystalline fluorite-type Ca1-xSnxF2 solid solution. In both materials, tin(II) is covalently bonded to fluorine, and thus carries a stereoactive non-bonding electronic pair. The electrical conductivity of CaSn2F6 was measured by the complex impedance method. The CaSn2F6 material was found to be a mixed conductor (τi = 0.50), with a F- conductivity a little below that of α-SnF2. On heating to 250°C, it decomposes irreversibly to give SnF2 and probably amorphous CaF2 (undetected).

Failure of the Frenkel Defect Model to Explain the Trend in Anionic Conductivity in the MF2 Fluorite Structure and Related MSnF4 Materials

1994 ◽  
Vol 369 ◽  
Author(s):  
Georges Denes
Keyword(s):  
Fluorite Structure ◽  
Fluoride Ion ◽  
Defect Model ◽  
Fluoride Ions ◽  
Frenkel Defect ◽  
Ion Motion ◽  
Frenkel Defects ◽  
Fluorite Type ◽  
High Fluoride ◽  
Anionic Conductivity

AbstractThe high fluoride ion conductivity of fluorite type MF2 has been attributed tothe fact that half of the F8 cubes present in this structure are empty and therefore, are potential vacant sites for interstitial fluoride ions in the formation of Frenkel defects. However, the model of long range ion motion through Frenkel defects by use of empty F8 cubes is in contradiction with: (i) the little difference between the conductivities of CaF2 and BaF2, (ii) the conductivity of β-PbF2 being much larger than that of BaF2, and (iii) the much higher performance of MSnF4 even though there is no empty cube to form Frenkel defects in the MSnF4 structures.

Preparation and Characterization of Pb2SnF6, The First Lead(II)-TIN(II) Fluoride that is a Superstructure of A-PbF2

2002 ◽  
Vol 755 ◽  
Author(s):  
Raimondo Calandrino ◽  
Anthony Collin ◽  
Georges Dénés ◽  
Morgane Logiou ◽  
M. Cecilia Madamba
Keyword(s):  
Aqueous Solution ◽  
Lattice Distortion ◽  
The Other ◽  
Fluoride Ion ◽  
Fluorite Type ◽  
New Phase ◽  
Ion Conductors

ABSTRACTAll the known phases in the PbF2/SnF2 system have structures derived from the fluorite-type β-PbF2, and are either disordered, and therefore cubic, or ordered with lattice distortion and superstructures. In addition, they are the highest performance fluoride-ion conductors, with PbSnF4 being the very best. In this work, a new phase, Pb2SnF6 has been prepared and characterized. Contrary to the other lead(II) tin(II) fluorides known up to date, the structure of Pb2SnF6 is a superstructure of a-PbF2, instead of β-PbF2, with a large (4 × 4) bidimensional supercell. Pb2SnF6 is prepared by the reaction of a-PbF2 with an aqueous solution of SnF2.

Use of Mössbauer Spectroscopy for the Characterization of Order/Disorder Phenomena in Tin(II) Containing Ionic Conductors and for Making Predictions Regarding Possible Electron Contribution to the Conduction

1998 ◽  
Vol 548 ◽  
Author(s):  
Georges Dénès ◽  
M. Cecilia Madamba ◽  
Abdualhafeed Muntasar ◽  
Alena Peroutka ◽  
Korzior Tam ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Mossbauer Spectroscopy ◽  
Fluorite Structure ◽  
Mixed Conductor ◽  
Fluoride Ion ◽  
Ionic Conductors ◽  
Mößbauer Spectroscopy ◽  
Electron Contribution ◽  
Fluorite Type

ABSTRACTMössbauer spectroscopy has been seldom used for the characterization of ionic conductors. However, since the introduction of divalent tin in MF2 fluorites (M = Sr, Pb and Ba) to form MSnF4, PbSn4F10 or the Pb1−xSnxF2 solid solution, all of which have structures closely related to the fluorite type, results in an enhancement of the fluoride ion conductivity by up to three orders of magnitude, and since 119 Sn is the second best Mössbauer nuclide, it seems that the Mössbauer technique could provide useful information about how tin(II) modifies the fluorite structure and leads to such a tremendous enhancement of the fluoride ion mobility. The MF2/SnF2 systems contain some number of materials that show order/disorder phenomena (between M and Sn, and also between different fluorine atoms) which make it difficult to understand them from diffraction data only. Mössbauer spectroscopy has been invaluable in helping understand the local structure at tin. By probing the valence electronic structure of tin, we can also make predictions on the possible long range mobility of the tin(II) non-bonded electron pair, which would make the material an electronic conductor or a mixed conductor.

Structural and Electrical Characterization of Shaped Beam Laser Recrystallized Polysilicon on Amorphous Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
T. J. Stultz ◽  
J. F. Gibbons
Keyword(s):  
Grain Size ◽  
Electrical Characterization ◽  
Grain Structure ◽  
Electrical Characteristics ◽  
Shaped Beam ◽  
Beam Laser ◽  
Cw Laser ◽  
Amorphous Substrates ◽  
Circular Beam

ABSTRACTStructural and electrical characterization of laser recrystallized LPCVD silicon films on amorphous substrates using a shaped cw laser beam have been performed. In comparing the results to data obtained using a circular beam, it was found that a significant increase in grain size can be achieved and that the surface morphology of the shaped beam recrystallized material was much smoother. It was also found that whereas circular beam recrystallized material has a random grain structure, shaped beam material is highly oriented with a <100> texture. Finally the electrical characteristics of the recrystallized film were very good when measured in directions parallel to the grain boundaries.

Vapor Deposition Polymerization and Electrical Characterization of TPD Thin Films

2011 ◽  
Vol E94-C (2) ◽  
pp. 157-163 ◽  
Author(s):  
Masakazu MUROYAMA ◽  
Ayako TAJIRI ◽  
Kyoko ICHIDA ◽  
Seiji YOKOKURA ◽  
Kuniaki TANAKA ◽  
...  
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Electrical Characterization

Electrical Characterization of Different Failure Modes in Sub-100 nm Devices Using Nanoprobing Technique

2009 ◽  
Author(s):  
E. Hendarto ◽  
S.L. Toh ◽  
J. Sudijono ◽  
P.K. Tan ◽  
H. Tan ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Focused Ion Beam ◽  
Failure Modes ◽  
Ion Beam ◽  
Electrical Characterization ◽  
Nickel Silicide ◽  
Fault Isolation ◽  
Technology Nodes ◽  
Scanning Electron

Abstract The scanning electron microscope (SEM) based nanoprobing technique has established itself as an indispensable failure analysis (FA) technique as technology nodes continue to shrink according to Moore's Law. Although it has its share of disadvantages, SEM-based nanoprobing is often preferred because of its advantages over other FA techniques such as focused ion beam in fault isolation. This paper presents the effectiveness of the nanoprobing technique in isolating nanoscale defects in three different cases in sub-100 nm devices: soft-fail defect caused by asymmetrical nickel silicide (NiSi) formation, hard-fail defect caused by abnormal NiSi formation leading to contact-poly short, and isolation of resistive contact in a large electrical test structure. Results suggest that the SEM based nanoprobing technique is particularly useful in identifying causes of soft-fails and plays a very important role in investigating the cause of hard-fails and improving device yield.

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