Epitaxial Growth of fee Fe and Cu Films on Diamond

1993 ◽  
Vol 313 ◽  
Author(s):  
D.P. Pappas ◽  
J.W. Glesener ◽  
V.G. Harris ◽  
J.J. Krebs ◽  
Y.U. Idzerda ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
Copper Films ◽  
Face Centered Cubic ◽  
Continuous Film ◽  
X Ray ◽  
Cu Films ◽  
Face Centered ◽  
X Ray Absorption ◽  
Oriented Single Crystal

ABSTRACTThe growth of iron and copper films and multilayers on the (100) face of diamond has been achieved and studied by reflection high energy electron diffraction (RHEED), extended x-ray absorption fine structure (EXAFS), ferromagnetic resonance (FMR), and SQUID Magnetometry. RHEED and AES studies show that 2–3 atomic layers (AL) of Fe on C (100) forms a continuous film. The films as deposited at room temperature are disordered, and after a 350° C anneal displays a face-centered cubic structure. Subsequent layers of Cu on this epitaxial Fe film grow as an oriented, single crystal fee film. FMR and SQUID signals have been observed from the Fe films, showing that they are ferromagnetic.

Epitaxial Ni nanoparticles on CaF2(001), (110) and (111) surfaces studied by three-dimensional RHEED, GIXD and GISAXS reciprocal-space mapping techniques

2017 ◽  
Vol 50 (3) ◽  
pp. 830-839 ◽  
Author(s):  
S. M. Suturin ◽  
V. V. Fedorov ◽  
A. M. Korovin ◽  
N. S. Sokolov ◽  
A. V. Nashchekin ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
High Energy ◽  
Reciprocal Space ◽  
Mapping Technique ◽  
Face Centered Cubic ◽  
X Ray ◽  
Cubic Lattice ◽  
Face Centered

The development of growth techniques aimed at the fabrication of nanoscale heterostructures with layers of ferroic 3dmetals on semiconductor substrates is very important for their potential usage in magnetic media recording applications. A structural study is presented of single-crystal nickel island ensembles grown epitaxially on top of CaF2/Si insulator-on-semiconductor heteroepitaxial substrates with (111), (110) and (001) fluorite surface orientations. The CaF2buffer layer in the studied multilayer system prevents the formation of nickel silicide, guides the nucleation of nickel islands and serves as an insulating layer in a potential tunneling spin injection device. The present study, employing both direct-space and reciprocal-space techniques, is a continuation of earlier research on ferromagnetic 3dtransition metals grown epitaxially on non-magnetic and magnetically ordered fluorides. It is demonstrated that arrays of stand-alone faceted nickel islands with a face-centered cubic lattice can be grown controllably on CaF2surfaces of (111), (110) and (001) orientations. The proposed two-stage nickel growth technique employs deposition of a thin seeding layer at low temperature followed by formation of the islands at high temperature. The application of an advanced three-dimensional mapping technique exploiting reflection high-energy electron diffraction (RHEED) has proved that the nickel islands tend to inherit the lattice orientation of the underlying fluorite layer, though they exhibit a certain amount of {111} twinning. As shown by scanning electron microscopy, grazing-incidence X-ray diffraction (GIXD) and grazing-incidence small-angle X-ray scattering (GISAXS), the islands are of similar shape, being faceted with {111} and {100} planes. The results obtained are compared with those from earlier studies of Co/CaF2epitaxial nanoparticles, with special attention paid to the peculiarities related to the differences in lattice structure of the deposited metals: the dual-phase hexagonal close-packed/face-centered cubic lattice structure of cobalt as opposed to the single-phase face-centered cubic lattice structure of nickel.

Structural, morphological, and magnetic study of nanocrystalline cobalt-copper powders synthesized by the polyol process

1995 ◽  
Vol 10 (6) ◽  
pp. 1546-1554 ◽  
Author(s):  
G.M. Chow ◽  
L.K. Kurihara ◽  
K.M. Kemner ◽  
P.E. Schoen ◽  
W.T. Elam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Copper Powders ◽  
Face Centered ◽  
Increasing Temperature ◽  
X Ray Absorption

Nanocrystalline CoxCu100−x (4 ⋚ x ⋚ 49 at. %) powders were prepared by the reduction of metal acetates in a polyol. The structure of powders was characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), extended x-ray absorption fine structure (EXAFS) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy, and vibrating sample magnetometry (VSM). As-synthesized powders were composites consisting of nanoscale crystallites of face-centered cubic (fcc) Cu and metastable face-centered cubic (fcc) Co. Complementary results of XRD, HRTEM, EXAFS, NMR, and VSM confirmed that there was no metastable alloying between Co and Cu. The NMR data also revealed that there was some hexagonal-closed-packed (hcp) Co in the samples. The powders were agglomerated, and consisted of aggregates of nanoscale crystallites of Co and Cu. Upon annealing, the powders with low Co contents showed an increase in both saturation magnetization and coercivity with increasing temperature. The results suggested that during preparation the nucleation of Cu occurred first, and the Cu crystallites served as nuclei for the formation of Co.

Synchrotron X-ray Absorption Studies of Atomic-Level Alloying in Immiscible Mixtures

1998 ◽  
Vol 524 ◽  
Author(s):  
J.-H. He ◽  
P. J. Schilling ◽  
E. Ma
Keyword(s):  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
Atomic Level ◽  
High Energy Ball Milling ◽  
Edge Structure ◽  
X Ray ◽  
Energy Ball ◽  
Immiscible Mixtures ◽  
X Ray Absorption

ABSTRACTAn X-ray absorption beamline has been developed recently at the electron storage ring of the LSU Center for Advanced Microstructures and Devices. Using Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES), we have studied the local atomic environments in immiscible mixtures processed by high-energy ball milling, a mechanical alloying technique involving heavy deformation. By examining the local coordination and bond distances, it is concluded that atomic-level alloying can indeed be induced between Cu and Fe through milling at room temperature, forming substitutional fcc and bcc solid solutions. In addition to single-phase regions, a two-phase region consisting of fcc/bcc solutions has been found after milling at both room temperature and liquid nitrogen temperature. In contrast to the Cu-Fe system, solid solution formation is not detectable in milled Ag-Fe and Cu-Ta mixtures. This work demonstrates the power of synchrotron EXAFS/XANES experiments in monitoring nonequilibrium alloying on the atomic level. At the same time, the results provide direct experimental evidence of the capability as well as limitations of high-energy ball milling to form alloys in positive-heat-of-mixing systems.

Temperature Dependent Structural Studies of K- and RB- Doped C60

1992 ◽  
Vol 270 ◽  
Author(s):  
Otto Zhou ◽  
Qing Zhu ◽  
Gavin B.M. Vaughan ◽  
John E. Fischer ◽  
Paul A. Heiney ◽  
...  
Keyword(s):  
Room Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Temperature Dependent ◽  
X Ray ◽  
Analysis Techniques ◽  
Temperature Range ◽  
Face Centered ◽  
Thermal Analysis Techniques ◽  
Bcc Phase

ABSTRACTThe temperature dependent structural evolutions of RbxC60 (x = 3, 5, 6) and K4C60 were studied using both in-house andsynchrotron x-ray powder diffraction and thermal analysis techniques over a temperature range of 10K - 673K. The superconducting face centered-cubic (fcc) Rb3C60 and the body centered-tetragonal (bct) M4C60(M = K, Rb) phases are found to be line compounds in this temperature range, while the body centered-cubic (bcc) phase forms a solid solution in which the solubility of vacant M sites increases with temperature. The orientation of the C60 molecules in the K4C60 phase was analyzed. A crystalline fcc Rb1C60 phase is stable only above room temperature.

Microstructure and electronic behavior of PtPd@Pt core-shell nanowires

2010 ◽  
Vol 25 (4) ◽  
pp. 711-717 ◽  
Author(s):  
Wei-Qiang Han ◽  
Dong Su ◽  
Michael Murphy ◽  
Matthew Ward ◽  
Tsun-Kong Sham ◽  
...  
Keyword(s):  
Shell Structure ◽  
Phase Transfer ◽  
Core Shell ◽  
Face Centered Cubic ◽  
Edge Structure ◽  
X Ray ◽  
One Step ◽  
Core Shell Structure ◽  
Face Centered ◽  
X Ray Absorption

PtPd@Pt core-shell ultrathin nanowires were prepared using a one-step phase-transfer approach. The diameters of the nanowires range from 2 to 3 nm, and their lengths are up to hundreds of nanometers. Line scanning electron energy loss spectra showed that PtPd bimetallic nanowires have a core-shell structure, with a PtPd alloy core and a Pt monolayer shell. X-ray absorption near edge structure (XANES) spectra reveal that a strong Pt-Pd interaction exists in this nanowire system in that there is PtPd alloying and/or interfacial interaction. Extended x-ray absorption fine structures (EXAFS) further confirms the PtPd@Pt core-shell structure. The bimetallic nanowires were determined to be face-centered cubic structures. The long-chain organic molecules of n-dodecyl trimethylammonium bromide and octadecylamine, used as surfactants during synthesis, were clearly observed using aberration-corrected TEM operated at 80 KV. The interaction of Pt and surfactants was also revealed by EXAFS.

scholarly journals The Rolling Texture of Cu3Au

Texture ◽  
1974 ◽  
Vol 1 (3) ◽  
pp. 143-150 ◽  
Author(s):  
R. A. Vandermeer ◽  
J. C. Ogle
Keyword(s):  
Room Temperature ◽  
Pure Copper ◽  
Rolling Texture ◽  
Wire Drawing ◽  
Face Centered Cubic ◽  
Long Range Order ◽  
X Ray Diffraction ◽  
X Ray ◽  
Partial Dislocations ◽  
Face Centered

The rolling texture of Cu3Au has been investigated by X-ray diffraction. At room temperature, independently of the degree of long-range order, Cu3Au developed a mixed or “hybrid” texture; it consisted of elements of each of the prototype face-centered cubic textures characterized by pure copper and 70/30 brass. However, on rolling at 77 K the alloy in the disordered state was significantly more “brass-like” than when it was fully ordered. This result may be explained by a stacking fault energy texture reversal analogous to that observed in wire drawing at low SFE. The lack of twinning (or other deformation mechanism such as slip by partial dislocations) in the ordered alloy could be responsible for this reversal.

scholarly journals Cation Distribution in Natural Chromites from Oman

1996 ◽  
Vol 1 (1) ◽  
pp. 55
Author(s):  
Z. Al-Alawi ◽  
A.M. Gismelseed ◽  
A.A. Yousif ◽  
M.A. Worthing ◽  
H.H. Sutherland ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Atomic Concentration ◽  
X Ray ◽  
Diffraction Patterns ◽  
Face Centered ◽  
Mössbauer Analysis ◽  
Scanning Electron

Two specimens or natural chromite from the Oman ophiolite were studied using Mossbauer Spectroscopy (MS), X-ray Diffraction (XRD). and Scanning Electron Microscopy (SEM). The diffraction patterns obtained at room temperature showed that the two specimens have a face-centered cubic spinal structure. Their Mossbauer spectra at 295 K. 160 K and 78 K have been fitted to three doublets. assigned to two Fe 2+ at the tetrahedral (A1+,A2) sites and one Fe1+ at the octahedral (B) site. The ferrous-ferric ratio obtained from the Mossbauer analysis together with the atomic concentration derived from the microprobe data are used to derive the chemical formulae for the two specimens. The data also supports also supports  a model of ordered caution distribution in the specimens examined.

scholarly journals Structural, Thermal, Optical, Electrical, and Adhesive Characteristics of FePdB Thin Films

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Yuan-Tsung Chen
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Room Temperature ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Adhesive Properties ◽  
X Ray ◽  
Face Centered ◽  
Xrd Patterns

To study the structural, thermal, electrical, optical, and adhesive properties of magnetic FePdB thin films, 25–200-Å-thick Fe40Pd40B20and Fe60Pd20B20films were deposited on a glass substrate by direct current (DC) magnetron sputtering at room temperature (RT). X-ray diffraction (XRD) patterns indicated that the 25–75-Å-thick Fe40Pd40B20and Fe60Pd20B20films were amorphous, whereas the 100–200-Å-thick Fe40Pd40B20and Fe60Pd20B20films were crystalline, with a face-centered cubic (FCC) FePd (111) textured structure. The activation energy of the Fe40Pd40B20and Fe60Pd20B20thin films decreased as thickness was increased. The 25-Å-thick Fe40Pd40B20film exhibited the highest resistivity, whereas the 200-Å-thick Fe60Pd20B20film exhibited the lowest resistivity. Increasing the thickness and crystallization reduced transmission. The Fe40Pd40B20thin films exhibited higher surface energy and stronger adhesion than did Fe60Pd20B20thin films.

Influence of Cu Content on the Microstructure, Mechanical, and Tribological Properties of ZrN–Cu Films

NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850035 ◽  
Author(s):  
Tong Chen ◽  
Lihua Yu ◽  
Hongbo Ju ◽  
Junhua Xu ◽  
Shinji Koyama
Keyword(s):  
Tribological Properties ◽  
Room Temperature ◽  
Composite Films ◽  
Rf Magnetron Sputtering ◽  
Face Centered Cubic ◽  
Cu Films ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
Cu Content ◽  
Face Centered

A series of ZrN–Cu nano-composite films were deposited using the RF magnetron sputtering system. The microstructure, mechanical properties and tribological properties were investigated. The results showed that ZrN–Cu films were composed of face-centered cubice (fcc)-ZrN and face-centered cubic (fcc)-Cu. With the increase of Cu content, the hardness of ZrN–Cu composite film increased slowly first and then decreased rapidly. The maximum hardness value was 34.6[Formula: see text]GPa at 16[Formula: see text]at.% Cu. At room temperature, the coefficient of friction (Cof.) of ZrN–Cu films were lower than the ZrN film. When the content of Cu was lower than 39[Formula: see text]at.%, the wear rate of ZrN–Cu films were lower than the ZrN film. When the temperature of tribological testing was between 200–700[Formula: see text]C, the Cof. of ZrN–Cu films at 16[Formula: see text]at.% Cu were lower than ZrN film, while the wear rates were higher than the ZrN film. In summary, the addition of Cu improved the hardness and tribological properties of the ZrN–Cu film at room temperature, and decreased the Cof. of the ZrN-Cu during 200–700[Formula: see text]C.

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