Structural and Chemical Properties of MBE Grown Niobium Overlayers on (110) Rutile

1996 ◽  
Vol 441 ◽  
Author(s):  
J. Marien ◽  
T. Wagner ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Chemical Properties ◽  
High Energy ◽  
Initial Growth ◽  
High Energy Electron ◽  
Transmission Electron ◽  
Different Temperatures ◽  
And Chemical Properties

AbstractThin Nb films were grown by MBE in a UHV chamber at two different temperatures (50°C and 950°C) on the (110) surface of TiO2 (rutile).At a growth temperature of 50°C, reflection high energy electron diffraction (RHEED) revealed epitaxial growth of Nb on rutile: (110)[001] TiO2 ¦¦ (100)[001] Nb. In addition, investigations with Auger electron spectroscopy (AES) revealed that a chemical reaction took place between the Nb overlayer and the TiO2 substrate at the initial growth stage. A 2 nm thick reaction layer at the Nb/TiO2 interface has been identified by means of conventional transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM).At a substrate temperature of 950°C, during growth, the Nb film was oxidized completely, and NbO2 grew epitaxially on TiO2. The structure and the chemical composition of the overlayers have been investigated by RHEED, AES, CTEM and HRTEM. Furthermore, it was determined that the reaction of Nb with TiO2 is governed by the defect structure of the TiO2 and the relative oxygen affinities of Nb and TiO2.

Compliance at the GaSb/GaP Interface by Misfit Dislocations Array

2011 ◽  
Vol 324 ◽  
pp. 85-88
Author(s):  
Salim El Kazzi ◽  
Ludovic Desplanque ◽  
Christophe Coinon ◽  
Yi Wang ◽  
Pierrre Ruterana ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Energy ◽  
Misfit Dislocations ◽  
Initial Growth ◽  
Electron Diffraction Analysis ◽  
High Energy Electron ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

We study the initial growth of 10 monolayers (MLs) of GaSb on a (001) GaP substrate. Transmission electron microscopy and reflection high energy electron diffraction analysis show that an Sb-rich GaP surface promotes the formation of a 90° misfit dislocation array at the epi-substrate interface. Using atomic force microscopy, we investigate the influence of the growth temperature and the growth rate on the formation and the shape of GaSb islands.

MBE-Grown Epitaxial Co/Cr Superlattices

1991 ◽  
Vol 231 ◽  
Author(s):  
W. Vavra ◽  
S. Elagoz ◽  
Roy Clarke ◽  
C. Uher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
High Energy ◽  
Squid Magnetometry ◽  
High Energy Electron ◽  
Deposition Rates ◽  
Saturation Field ◽  
Transmission Electron ◽  
Hall Effect Measurements

AbstractA series of epitaxial Co/Cr superlattices has been grown by molecular beam epitaxy. The Cr is in a metastable hcp phase as confirmed by transmission electron microscopy, selected area diffraction, and reflection high energy electron diffraction. The Cr layers are 10Å thick in all samples while the Co layers are varied from 12Å to 40Å. The diffusion between Co and Cr is studied by SQUID magnetometry and indicates step-like interfaces in the best samples. Interfacial sharpness has also been found to be unusually sensitive to Co deposition rates, and in contrast with other superlattice systems, we find that sharper interfaces enhance parallel anisotropy. Hall effect measurements of the saturation field are within 10% of SQUID values. Magnetoresistance at 4.2K is only 1/3% which we believe is a consequence of the high density of states at the Fermi level of hcp Cr.

Growth and Thermal Stability of Thin Niobium Overlayers on (0001) Sapphire Substrates

1995 ◽  
Vol 403 ◽  
Author(s):  
T. Wagner ◽  
M. Lorenz ◽  
P. A. Langjahr ◽  
M. Ruhle
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Deposition Temperature ◽  
High Energy ◽  
High Energy Electron ◽  
Epitaxial Relationship ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Thermal Stability Of

AbstractThin Nb films were deposited by MBE on (0001)α-Al2O3 in UHV. At a substrate temperature of 800°C, reflection high energy electron diffraction (RHEED) revealed that the film grew with the orientation relationship (planes of similar symmetry are parallel to each other): (0001)α-Al2O3 ‖ (111)Nb; [2110]α-Al2O3 ‖ [110]Nb. Investigations with conventional transmission electron. microscopy (CTEM) revealed that the film was not perfectly epitaxial after deposition. Small Nb grains with different orientations were embedded in the epitaxial Nb film. During annealing at temperatures well above the deposition temperature, secondary grain growth of the small embedded Nb grains occured, leading to a different epitaxial relationship between the Nb film and the sapphire: (0001)α-Al2O3 ‖ (110)Nb; [0110]α-Al2O3 ‖ [001]Nb.

High-energy electron irradiation study of relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 and Pb1−xLax[Mg(1+x)/3Nb(2−x)/3]O3 by transmission electron microscopy

2002 ◽  
Vol 17 (10) ◽  
pp. 2615-2620 ◽  
Author(s):  
Shu Miao ◽  
Jing Zhu ◽  
X. W. Zhang ◽  
X. H. Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Irradiation ◽  
High Energy ◽  
High Energy Electron ◽  
Beam Radiation ◽  
Practical Applications ◽  
Electron Beam Radiation ◽  
Transmission Electron ◽  
Crystallographic Orientation Relationship

The electron irradiation sensitivities of Pb(Mg1/3Nb2/3)O3 (PMN) and Pb1−xLax[Mg(1+x)/3Nb(2−x)/3]O3 (PLMN) ceramics were investigated by transmission electron microscopy. Nanoscale Pb particles formed in these materials under electron beam radiation. It was found that these fine Pb particles generally had a preferred crystallographic orientation relationship with the PMN/PLMN host and always existed at positions slightly rich in Mg2+. A preliminary mechanism involving defect chemistry reactions is proposed to interpret this unusual Pb precipitation. Possible limitations to the practical applications of these materials are discussed.

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