The importance of the Mg–Mg interaction in Mg3Sb2–Mg3Bi2 shown through cation site alloying

2020 ◽  
Vol 8 (4) ◽  
pp. 2033-2038 ◽  
Author(s):  
Max Wood ◽  
Kazuki Imasato ◽  
Shashwat Anand ◽  
Jiong Yang ◽  
G. Jeffrey Snyder
Keyword(s):  
Cation Site ◽  
Alloy Scattering

Herein we study the effect alloying Yb onto the octahedral cite of Te doped Mg3Sb1.5Bi0.5 has and show that the reduction in mobility can be explained with an alloy scattering argument due to disrupting the Mgoctahedral–Mgtetrahedral interaction.

Interfacial roughnes and alloy scattering in the InGaAs/InAlAs/InP system grown by ALE and LAMBE

1991 ◽  
Vol 9 (4) ◽  
pp. 467-469
Author(s):  
A. Christou ◽  
Z. Hatzopoulos ◽  
A. Dimoulas ◽  
G. Kiriakidis
Keyword(s):  
Alloy Scattering

Nature and mechanism of ilmenite alteration: a Mössbauer and X-ray diffraction study of oxidized ilmenite from the Beja-Acebuches Ophiolite Complex (SE Portugal)

2002 ◽  
Vol 66 (3) ◽  
pp. 421-430 ◽  
Author(s):  
J. C. Waerenborgh ◽  
J. Figueiras ◽  
A. Mateus ◽  
M. Gonçalves
Keyword(s):  
Mössbauer Spectroscopy ◽  
Mossbauer Spectroscopy ◽  
X Ray Diffraction ◽  
Ophiolite Complex ◽  
Cation Site ◽  
X Ray ◽  
Mößbauer Spectroscopy ◽  
Ilmenite Structure ◽  
Optical Evidence ◽  
Excess Fe

AbstractIlmenites from the least-altered rocks of the Beja-Acebuches Ophiolite Complex (SE Portugal), with low Ti values and excess Fe, despite rare optical evidence of hematite exsolution, were studied by 57Fe Mössbauer spectroscopy and X-ray diffraction. According to single-crystal XRD the sequence of alternate layers characteristic of the ideal ilmenite structure is preserved, the excess Fe being accommodated in the Ti layers. No superparamagnetic oxides were detected by 57Fe Mössbauer spectroscopy. The typical spectra of bulk αFe2O3 and of Fe3+-containing ilmenite, in the paramagnetic state above 49 K and magnetically ordered at 6 K, are observed. The average degree of oxidation of the ilmenites, estimated from the chemical analysis assuming ideally stoichiometric full cation site occupancies, is also confirmed by 57Fe Mössbauer data. Since our crystal chemistry study gave no evidence of crypto-exsolution textures within the ilmenite with the observed compositions, fast cooling from magmatic temperatures and decomposition of ilmenite in supergene conditions is suggested.

Si1−xGex Bulk Crystals Growth and PN Junction Formation by Diffusing Phosphorus

1999 ◽  
Vol 607 ◽  
Author(s):  
S. Kato ◽  
T. Horikoshi ◽  
T. Ohkubo ◽  
T. Iida ◽  
Y. Takano
Keyword(s):  
Silicon Germanium ◽  
Bulk Crystals ◽  
Temperature Dependent ◽  
Alloy Scattering ◽  
Self Diffusion ◽  
Pn Junction ◽  
Current Voltage ◽  
Vertical Bridgman ◽  
Current Voltage Characteristics ◽  
P Type

AbstractThe bulk crystal of silicon germanium was grown by vertical Bridgman method with germanium composition, x, varying from 0.6 to 1.0. The temperature dependent variation of the mobility is indicative of alloy scattering dominantly for the bulk wafer. Phosphorus was diffused in as-grown p-type bulk wafer at 850 °C to form pn-junction, and the diffusion coefficient of phosphorus was evaluated as a function of x. The diffusion behavior of phosphorus in silicon germanium is closely correlated with the germanium self-diffusion with changing x. For specimens with lower content x, P concentration profiles indicated “kink and tail” shape, while it was not observed for higher x. For current-voltage characteristics measurement, an ideality factor was obtained.

scholarly journals Thortveitite-type Tm2Si2O7

2014 ◽  
Vol 70 (7) ◽  
pp. i34-i35 ◽  
Author(s):  
Volker Kahlenberg ◽  
Paul Aichholzer
Keyword(s):  
Ambient Pressure ◽  
Point Group ◽  
Structure Type ◽  
Group Symmetry ◽  
Site Symmetry ◽  
Cation Site ◽  
Bond Lengths ◽  
Flux Synthesis ◽  
Distorted Octahedral ◽  
The Individual

Single crystals of dithulium disilicate, Tm2Si2O7, were obtained in flux synthesis experiments in the system SiO2–Tm2O3–LiF at ambient pressure. The compound belongs to the group of sorosilicates,i.e.it is based on [Si2O7]-units and crystallizes in the thortveitite (Sc2Si2O7) structure type. The Tm3+cation (site symmetry .2.) occupies a distorted octahedral site, with Tm—O bond lengths in the range 2.217 (4)–2.289 (4) Å. Each of the octahedra shares three of its edges with adjacent [TmO6] groups, resulting in the formation of layers parallel to (001). The individual [SiO4] tetrahedra are more regular,i.e.the differences between the bond lengths between Si and the bridging and non-bridging O atoms are not very pronounced. The layers containing the octahedra and the sheets containing the [Si2O7] groups (point group symmetry 2/m) form an alternating sequence. Linkage is provided by sharing common oxygen vertices.

Leucite-pollucite structure-type variability and the structure of a synthetic end-member calcium wairakite (CaAl2Si4O12·2H2O)

1998 ◽  
Vol 62 (2) ◽  
pp. 165-178 ◽  
Author(s):  
C. M. B. Henderson ◽  
A. M. T. Bell ◽  
S. C. Kohn ◽  
C. S. Page
Keyword(s):  
Rietveld Analysis ◽  
Structure Type ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Synthetic Sample ◽  
Cation Site ◽  
Wide Range ◽  
Angle Spinning ◽  
Cation Sites

AbstractThe structure of a synthetic end-member wairakite (CaAl2Si4O12·2H2O) has been determined using Rietveld analysis of high-resolution, synchrotron X-ray powder diffraction data, and 29Si and 27Al magic angle spinning nuclear magnetic resonance spectroscopy. The framework in the synthetic sample is more disordered than that in natural wairakite. Ca is distributed over the cavity cation sites M2, M12A, M12B in the approximate proportions 0.8:0.1:0.1, respectively, with M11 being vacant. 29Si MAS NMR data are consistent with about 80% of the Si occupying tetrahedral T11 and T12 sites linked to two Al atoms [Q4(2Al) silicons]. Tetrahedral and cavity cation site disorder are coupled so that Al mainly occupies T2 sites, with Ca in M12A and M12B being balanced by Al in T12A and T12B; T11A and T11B sites appear to only contain Si, in agreement with the M11 site being vacant. The crystal chemistries of the wide range of stoichiometries which crystallize with the leucite/pollucite structure-type are also reviewed, with particular attention being paid to the tetrahedral ordering configurations present in these phases, and the implications to crystallographic phase transitions.

Rietveld refinement of the solid-solution series: (Cu,Mg)SO4·H2O

1995 ◽  
Vol 10 (3) ◽  
pp. 189-194 ◽  
Author(s):  
C. L. Lengauer ◽  
G. Giester
Keyword(s):  
Solid Solution ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Solid Solution Series ◽  
Cation Site ◽  
Tg Analysis ◽  
X Ray ◽  
Solution Series

The kieserite-type solid-solution series of synthetic (Cu,Mg)SO4·H2O was investigated by TG-analysis and X-ray powder diffraction using the Rietveld method. Representatives with Cu≥20 mol% are triclinic distorted () analogous to the poitevinite (Cu,Fe)SO4·H2O compounds. Cation site ordering with preference of Cu for the more distorted M1 site was additionally proven by the structure refinement.

scholarly journals Synthesis, Structure and Magnetic Properties of NiFe3O5

2022 ◽  
Author(s):  
Ka Hong ◽  
Elena Solana ◽  
Mauro Coduri ◽  
Clemens Ritter ◽  
Paul Attfield
Keyword(s):  
Exchange Interactions ◽  
Neutron Diffraction Data ◽  
Cation Site ◽  
Cell Parameters ◽  
Site Distribution ◽  
Rich Variety ◽  
Ordered Phases ◽  
The Rich ◽  
Cation Size ◽  
Cation Sites

Abstract A new CaFe3O5-type phase NiFe3O5 (orthorhombic Cmcm symmetry, cell parameters a = 2.89126(7), b = 9.71988(21) and c = 12.52694(27) Å) has been synthesised under pressures of 12-13 GPa at 1200 °C. NiFe3O5 has an inverse cation site distribution and reveals an interesting evolution from M2+(Fe3+ )2Fe2+O5 to Fe2+(M2+ 0.5Fe3+ 0.5)2Fe3+O5 distributions over three distinct cation sites as M2+ cation size decreases from Ca to Ni. Magnetic susceptibility measurements show successive transitions at 275, ~150, and ~20 K and neutron diffraction data reveal a series of at least three spin-ordered phases with evolving propagation vectors k = [0 0 0] [0 ky 0]  [½ ½ 0] on cooling. The rich variety of magnetically ordered phases in NiFe3O5 likely results from frustration of Goodenough-Kanamori exchange interactions between the three spin sublattices, and further interesting magnetic materials are expected to be accessible within the CaFe3O5-type family.

Evidence for alloy scattering from pressure-induced changes of electron mobility in In1−xGaxAsyP1−y

1980 ◽  
Vol 16 (14) ◽  
pp. 560 ◽  
Author(s):  
A.R. Adams ◽  
H.L. Tatham ◽  
J.R. Hayes ◽  
A.N. El-Sabbahy ◽  
P.D. Greene
Keyword(s):  
Electron Mobility ◽  
Alloy Scattering ◽  
Induced Changes
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