New BCT Iron Phase in (100) Felr Superlattices

1993 ◽  
Vol 313 ◽  
Author(s):  
S. Andrieu ◽  
J. Hübsch ◽  
M. Piecuch ◽  
L. Hennet ◽  
H. FISCHER
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Molecular Beam ◽  
Two Dimensional ◽  
X Ray ◽  
Bcc Lattice ◽  
Iron Phase ◽  
Dimensional Growth ◽  
Weak Ferromagnetic ◽  
Second Order Phase Transition

ABSTRACTIn this paper, the synthesis of a new structure of iron in (100) Felr superlattices grown by Molecular Beam Epitaxy is reported. Two-dimensional growth up to 4 planes at 400K occurs, as shown by RHEED oscillations. Electron diffraction also gives evidence that the Fe lattice is pseudomorphic to the Ir one during the 2D-growth, and relaxes to the bcc lattice for thicker deposits. An X-Ray analysis shows that the Fe structure is a body centered tetragonal one with a c/a ratio close to 1.25. This phase is observed to be non-Magnetic at room temperature, as a weak ferromagnetic behaviour is observed at low temperatures, except at small Ir thicknesses. This is the evidence of the existence of a low spin phase which seems to undergo a second order phase transition with the atomic volume of iron.

scholarly journals Dielectric Function of AlN Grown on Si (111) by MBE

1999 ◽  
Vol 572 ◽  
Author(s):  
Stefan Zollner ◽  
Atul Konkar ◽  
R. B. Gregory ◽  
S. R. Wilson ◽  
S. A. Nikishin ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Buffer Layers ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Growth Morphology ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth ◽  
Peak Widths

ABSTRACTWe measured the ellipsometric response from 0.7–5.4 eV of c-axis oriented AlN on Si (111) grown by molecular beam epitaxy. We determine the film thicknesses and find that for our AlN the refractive index is about 5–10% lower than in bulk AlN single crystals. Most likely, this discrepancy is due to a low film density (compared to bulk AlN), based on measurements using Rutherford backscattering. The films were also characterized using atomic force microscopy and x-ray diffraction to study the growth morphology. We find that AlN can be grown on Si (111) without buffer layers resulting in truely two-dimensional growth, low surface roughness, and relatively narrow x-ray peak widths.

scholarly journals Half-metals and half-semiconductors in a transition metal doped SnSe2 monolayer: a first-principles study

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44499-44504 ◽  
Author(s):  
Xuming Wu ◽  
Jiangchao Han ◽  
Yulin Feng ◽  
Guanpeng Li ◽  
Cong Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
First Principles ◽  
Room Temperature ◽  
Molecular Beam ◽  
Ferromagnetic Behavior ◽  
Two Dimensional ◽  
Half Metals ◽  
Metal Doped ◽  
Mn Doped ◽  
Weak Ferromagnetic

Recently, a new two-dimensional (2D) semiconductor SnSe2 monolayer has been grown by molecular beam epitaxy, and weak ferromagnetic behavior above room temperature in Mn-doped SnSe2 thin films was also observed experimentally.

In as a Surfactant for the Growth of AlGaN/GaN Heterostructures by Plasma Assisted MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
E. Monroy ◽  
N. Gogneau ◽  
E. Bellet-Amalnc ◽  
F. Enjalbert ◽  
J. Barjon ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Molecular Beam Epitaxy Growth ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth

ABSTRACTIn this paper, we study the surfactant capability of In for the growth of AlGaN/GaN heterostructures by plasma-assisted molecular beam epitaxy. Growth conditions were determined to have a self-regulated 1×1 In adlayer on AlxGa1-xN (0001). The presence of this In film favors two dimensional growth of AlGaN under stoichiometric conditions, and inhibits the formation of metal droplets on the surface. The quality of these layers was assessed by high resolution X-ray diffraction, atomic force microscopy and photoluminescence.

PSEUDOMORPHIC GeSiSn LAYERS IN STRAINED HETEROSTRUCTURES

2018 ◽  
Vol 20 (4) ◽  
pp. 218-223
Author(s):  
A.I. Nikiforov ◽  
V.A. Timofeev ◽  
A.I. Yakimov ◽  
V.I. Mashanov ◽  
I.D. Loshkarev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Three Dimensional ◽  
Multilayer Structures ◽  
Two Dimensional ◽  
X Ray ◽  
Lattice Constants ◽  
Growth Regime ◽  
Transmission Electron ◽  
Dimensional Growth

The formation of pseudomorphous GeSiSn layers directly on Si have been investigated. The transition from two-dimensional growth regime to three-dimensional of the GeSiSn film on Si(100) was studied for different mismatch with silicon and growth temperatures. A possibility of synthesis of multilayer structures by molecular beam epitaxy was shown. The crystal lattice constants were determined using the high-resolution transmission electron microscopy and X-ray diffractometry. The p-i-n-diodes based on multilayer GeSiSn/Si structures were created which demonstrated the photoresponse increasing by several orders of magnitude in comparison the Sn-free structures at an increase in the Sn content. Nanostructures based on GeSiSn layers have demonstrated the photoluminescence at 0.6−0.85 eV.

Magnetic Properties of Sputtered Fe-O and Co-O Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
D. V. Dimitrov ◽  
A. S. Murthy ◽  
G. C. Hadjipanayis ◽  
C. P. SWANN
Keyword(s):  
Grain Size ◽  
Low Temperatures ◽  
Room Temperature ◽  
Oxide Films ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Large Shift ◽  
X Ray ◽  
Grain Size And Shape ◽  
Spherical Grains

AbstractFe-O and Co-O films were prepared by DC magnetron sputtering in a mixture of Ar and O2 gases. By varying the oxygen to argon ratio, oxide films with stoichiometry FeO, Fe3O4, α-Fe2O3, CoO and Co3O4 were produced. TEM studies showed that the Fe – oxide films were polycrystalline consisting of small almost spherical grains, about 10 nm in size. Co-O films had different microstructure with grain size and shape dependent on the amount of oxygen. X-ray diffraction studies showed that the grains in Fe-O films were randomly oriented in contrast to Co-O films in which a <111> texture was observed. Pure FeO and α-Fe2O3 films were found to be superparamagnetic at room temperature but strongly ferromagnetic at low temperatures in contrast to the antiferromagnetic nature of bulk samples. A very large shift in the hysteresis loop, about 3800 Oe, was observed in field cooled Co-CoO films indicating the presence of a large unidirectional exchange anisotropy.

GaSb layers with low defect density deposited on (001) GaAs substrate in two-dimensional growth mode using molecular beam epitaxy

2019 ◽  
Vol 19 (4) ◽  
pp. 542-547
Author(s):  
Agata Jasik ◽  
Iwona Sankowska ◽  
Andrzej Wawro ◽  
Jacek Ratajczak ◽  
Dariusz Smoczyński ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Defect Density ◽  
Growth Mode ◽  
Two Dimensional ◽  
Dimensional Growth

Morphology of Silver Thin Films Deposited on TiO2(110) Surfaces

1998 ◽  
Vol 05 (01) ◽  
pp. 387-392 ◽  
Author(s):  
D. Abriou ◽  
D. Gagnot ◽  
J. Jupille ◽  
F. Creuzet
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Two Dimensional ◽  
Silver Films ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Silver Deposits ◽  
Silver Thin Films

The growth mode of silver films deposited at room temperature on TiO 2(110) surfaces has been examined by means of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum (UHV) conditions, On clean vacancy-free TiO 2(110) surfaces, 0.1-nm-thick (on average) Ag deposits form a two-dimensional (2D) layer. When the thickness of the silver overlayer is increased, 3D clusters are shown to appear while the 2D film is preserved, furthermore, the influence of surface oxygen vacancies on the growth of Ag/TiO 2(110) is evidenced by well-characterized differences in the morphology of 9-nm-thick silver deposits.

Formation of ZnO Doped with Mn Thin Film by Electrodeposition and Magnetic Behaviour.

2005 ◽  
Vol 879 ◽  
Author(s):  
M. Abid ◽  
C. Terrier ◽  
J-P Ansermet ◽  
K. Hjort
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetic Behaviour ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doped Zno ◽  
Mn Doped ◽  
Weak Ferromagnetic

AbstractFollowing the theory, ferromagnetism is predicted in Mn- doped ZnO, Indeed, ferromagnetism above room temperature was recently reported in thin films as well as in bulk samples made of this material. Here, we have prepared Mn doped ZnO by electrodeposition. The samples have been characterized by X-ray diffraction and spectroscopic methods to ensure that the dopants are substitutional. Some samples exhibit weak ferromagnetic properties at room temperature, however to be useful for spintronics this material need additional carriers provided by others means.

scholarly journals An operando X-ray diffraction study of chloroaluminate anion-graphite intercalation in aluminum batteries

2018 ◽  
Vol 115 (22) ◽  
pp. 5670-5675 ◽  
Author(s):  
Chun-Jern Pan ◽  
Chunze Yuan ◽  
Guanzhou Zhu ◽  
Qian Zhang ◽  
Chen-Jui Huang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Negative Electrode ◽  
Discharge Voltage ◽  
Battery Life ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stage 4 ◽  
Graphite Intercalation ◽  
Battery Discharge

We investigated rechargeable aluminum (Al) batteries composed of an Al negative electrode, a graphite positive electrode, and an ionic liquid (IL) electrolyte at temperatures down to −40 °C. The reversible battery discharge capacity at low temperatures could be superior to that at room temperature. In situ/operando electrochemical and synchrotron X-ray diffraction experiments combined with theoretical modeling revealed stable AlCl4−/graphite intercalation up to stage 3 at low temperatures, whereas intercalation was reversible up to stage 4 at room temperature (RT). The higher-degree anion/graphite intercalation at low temperatures affords rechargeable Al battery with higher discharge voltage (up to 2.5 V, a record for Al battery) and energy density. A remarkable cycle life of >20,000 cycles at a rate of 6C (10 minutes charge time) was achievable for Al battery operating at low temperatures, corresponding to a >50-year battery life if charged/discharged once daily.

Facile Synthesis of 4,5-Dihydro-1,3,4-Thiadiazoles by 1,3-Dipolar Cycloaddition of Thioisomünchnones

2009 ◽  
Vol 62 (4) ◽  
pp. 356 ◽  
Author(s):  
Bárbara Sánchez ◽  
José Luis Bravo ◽  
María Josí Arívalo ◽  
Ignacio López ◽  
Mark E. Light ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Structure Elucidation ◽  
Room Temperature ◽  
Dipolar Cycloaddition ◽  
Two Dimensional ◽  
Facile Synthesis ◽  
X Ray ◽  
Mild Conditions ◽  
Nmr Techniques

The present paper summarizes a straightforward synthesis of 4,5-dihydro-1,3,4-thiadiazoles by the 1,3-dipolar cycloaddition of thioisomünchnones. These reactions have been carried out in dichloromethane and are essentially complete within 60 min at room temperature. Under such mild conditions the asymmetric version has been explored as well. Unequivocal structure elucidation has been accomplished by means of one- and two-dimensional NMR techniques as well as X-ray structure analysis.

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