Evolution of metastable phases during crystallization of pulsed laser deposited amorphous Al–Fe films

2003 ◽  
Vol 18 (2) ◽  
pp. 284-295 ◽  
Author(s):  
Sandip Bysakh ◽  
Puspendu Kumar Das ◽  
Kamanio Chattopadhyay
Keyword(s):  
Amorphous Phase ◽  
Pulsed Laser ◽  
Phase Evolution ◽  
The Body ◽  
Metastable Phases ◽  
Cubic Phase ◽  
Amorphous Thin Films ◽  
Transmission Electron ◽  
Ordered Phases ◽  
Vapor Quenching

Amorphous thin films of different Al–Fe compositions were produced by plasma/vapor quenching during pulsed laser deposition. The chosen compositions Al72Fe28, Al40Fe60, and Al18Fe82 correspond to Al5Fe2 and B2-ordered AlFe intermetallic compounds and α–Fe solid solution, respectively. The films contained fine clusters that increased with iron content. The sequences of phase evolution observed in the heating stage transmission electron microscopy studies of the pulsed laser ablation deposited films of Al72Fe28, Al40Fe60, and Al18Fe82 compositions showed evidence of composition partitioning during crystallization for films of all three compositions. This composition partitioning, in turn, resulted in the evolution of phases of compositions richer in Fe, as well as richer in Al, compared to the overall film composition in each case. The evidence of Fe-rich phases was the B2 phase in Al72Fe28 film, the L12- and DO3-ordered phases in Al40Fe60 film, and the hexagonal ε–Fe in the case of the Al18Fe82 film. On the other hand, the Al-rich phases were Al13Fe4 for both Al72Fe28 and Al40Fe60 films and DO3 and Al5Fe2 phases in the case of Al18Fe82 film. We believe that this tendency of composition partitioning during crystallization from amorphous phase is a consequence of the tendency of clustering of the Fe atoms in the amorphous phase during nucleation. The body-centered cubic phase has a nucleation advantage over other metastable phases for all three compositions. The amorphization of Al18Fe82 composition and the evolution of L12 and ε–Fe phases in the Al–Fe system were new observations of this work.

Early stages of the growth of BaTiO3 thin films studied by Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 706-707
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
Christopher Scarfone ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Room Temperature ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Cubic Phase ◽  
Transmission Electron ◽  
Tetragonal Form

Barium titanate (BaTiO3) may be used in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. In particular, the tetragonal form of BaTiO3, which is stable at room temperature, exhibits ferro-, pyro- and piezoelectric properties. It is desirable to form films of the tetragonal phase directly and thus to avoid formation of either amorphous or polycrystalline material or to form material of the non-ferroelectric cubic phase. Recently two techniques, pulsed-laser ablation and reactive evaporation, have been used to form BaTiO3 thin-films. In the present study BaTiO3 thin-films have been formed using the pulsed-laser ablation technique. Pulsed-laser ablation is now widely used to produce thin-films of the high temperature superconductors and has many advantages over other techniques, in particular the formation of films which maintain the stoichiometry of the target material and by controlling the processing conditions the formation of films having defined crystalline phases.

Transmission Electron Microscopy and High-Resolution Transmission Electron Microscopy Study of Nanostructure and Metastable Phase Evolution in Pulsed-Laser-Ablation–Deposited Ti–Si Thin Film

2004 ◽  
Vol 19 (4) ◽  
pp. 1118-1125 ◽  
Author(s):  
S. Bysakh ◽  
K. Mitsuishi ◽  
M. Song ◽  
K. Furuya ◽  
K. Chattopadhyay
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Ablation ◽  
High Resolution ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Phase Evolution ◽  
Nominal Composition ◽  
Ion Milling ◽  
Transmission Electron

Thin films with a nominal composition close to Ti62.5Si37.5 were deposited on NaCl substrate at room temperature by pulsed laser ablation to study the evolution of the intermetallic compound Ti5Si3 using a combination of high-resolution and in situ transmission electron microscopy. The as-deposited amorphous films contain Ti-rich clusters, which influence the phase evolution and the decomposition behavior of the amorphous film. These clusters influence the nucleation of a metastable fcc Ti solid solution (ao = 0.433 nm) with composition richer in Ti than Ti62.5Si37.5 as the first phase to crystallize at 773 K. The Ti5Si3 nanocrystals form later, and even at 1073 K they coexist with fine fcc Ti-rich nanocrystals. Subsequent Ar+ ion-milling of the crystallized film results in a loss of silicon. The composition change leads to the dissolution of the Ti5Si3 nanocrystals and evolution of a new metastable Ti-rich fcc phase (ao= 0.408 nm).

Transmission electron microscopy characterization of the microstructure of Cd3As2 films prepared by pulsed-laser evaporation

1987 ◽  
Vol 65 (8) ◽  
pp. 961-965 ◽  
Author(s):  
G. J. C. Carpenter ◽  
J. J. Dubowski ◽  
D. F. Williams
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pulsed Laser ◽  
The Body ◽  
Laser Evaporation ◽  
Transmission Electron ◽  
Transmission Electron Microscopy Characterization ◽  
Amorphous Substrates ◽  
Tetragonal Form ◽  
Microscopy Characterization

Transmission electron microscopy with an analytical X-ray system has been used to investigate Cd3As2 films prepared by pulsed-laser evaporation. The films were deposited on amorphous substrates at ~ 120 °C. They consisted mainly of a fine polycrystalline array. The crystal structure was identified as the body-centered tetragonal form of Cd3As2. No other crystallographic phase of Cd3As2 was observed. Some regions with amorphous or eutectic inclusions were also observed. These results have been correlated with the electrical properties of pulsed-laser evaporated Cd3As2 films.

Structural Studies of Pulsed-laser-deposited Ba4Fe4Ti3O16 Oxide Films

2000 ◽  
Vol 15 (6) ◽  
pp. 1389-1396 ◽  
Author(s):  
L. A. Bendersky ◽  
R. Maier ◽  
J. L. Cohn ◽  
J. J. Neumeier
Keyword(s):  
Perovskite Phase ◽  
Pulsed Laser ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Disordered Structure ◽  
No Formation ◽  
Disordered Phase ◽  
Transmission Electron ◽  
Initial Stage ◽  
Twinning Plane

For this paper the pulsed laser deposition on single-crystal MgO substrates of Ba4Fe4Ti3O16 target was studied by transmission electron microscopy and x-ray diffraction. The initial stage of the deposition resulted in the formation of the perovskite Ba(Fe, Ti)O3 phase in an epitaxial, cube-on-cube orientation relationship with a substrate. Further growth of the pseudo-cubic phase was interrupted by the formation of oriented grains with a disordered structure. This disordered structure had a mixture of lamellae of the cubic and hexagonal Ba(Fe, Ti)O3 phases. No formation of the Ba4Fe4Ti3O16 (E) phase was observed. Formation of the disordered phase was explained by the higher stability of hexagonal Ba(Fe, Ti)O3 where accommodation of Fe3+ occurred on a twinning plane. The development of the V-shape morphology and a limited number of orientations of the D structure were explained by the faceting and columnar morphology of the perovskite phase.

Substrate temperature dependence of structure and resistivity of SrRuO3 thin films grown by pulsed laser deposition on (100) SrTiO3

1999 ◽  
Vol 14 (11) ◽  
pp. 4385-4394 ◽  
Author(s):  
N. D. Zakharov ◽  
K. M. Satyalakshmi ◽  
G. Koren ◽  
D. Hesse
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Cubic Phase ◽  
Orthorhombic Structure ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Different Temperatures

The resistivity of SrRuO3 thin films on (001) SrTiO3 substrates grown at different temperatures by pulsed laser deposition is correlated to the microstructure. Films grown at 775 °C are of an orthorhombic structure, contain very few defects, and exhibit a low resistivity of 150 μΩ cm. Films grown at other temperatures contain a cubic phase and show higher resistivities. The defects present in the films, particularly twins and antiphase boundaries, are analyzed by high-resolution transmission electron microscopy, and their origin, as well as influence on film resistivity, is discussed.

Otoconia formation in the chick embryo

1983 ◽  
Vol 41 ◽  
pp. 572-573
Author(s):  
C.D. Fermin ◽  
M. Igarashi
Keyword(s):  
Chick Embryo ◽  
Inner Ear ◽  
Gallus Domesticus ◽  
The Body ◽  
Abnormal Behavior ◽  
Intensive Study ◽  
Basic Fuchsin ◽  
Gestational Period ◽  
Sensory Epithelia ◽  
Transmission Electron

Otoconia are microscopic geometric structures that cover the sensory epithelia of the utricle and saccule (gravitational receptors) of mammals, and the lagena macula of birds. The importance of otoconia for maintanance of the body balance is evidenced by the abnormal behavior of species with genetic defects of otolith. Although a few reports have dealt with otoconia formation, some basic questions remain unanswered. The chick embryo is desirable for studying otoconial formation because its inner ear structures are easily accessible, and its gestational period is short (21 days of incubation).The results described here are part of an intensive study intended to examine the morphogenesis of the otoconia in the chick embryo (Gallus- domesticus) inner ear. We used chick embryos from the 4th day of incubation until hatching, and examined the specimens with light (LM) and transmission electron microscopy (TEM). The embryos were decapitated, and fixed by immersion with 3% cold glutaraldehyde. The ears and their parts were dissected out under the microscope; no decalcification was used. For LM, the ears were embedded in JB-4 plastic, cut serially at 5 micra and stained with 0.2% toluidine blue and 0.1% basic fuchsin in 25% alcohol.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

Fin Level Defect Isolation Inside a FinFET Using Electron Beam Alteration of Current Flow

2017 ◽  
Author(s):  
H.J. Ryu ◽  
A.B. Shah ◽  
Y. Wang ◽  
W.-H. Chuang ◽  
T. Tong
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Focused Ion Beam ◽  
Current Flow ◽  
Ion Beam ◽  
The Body ◽  
Complete Understanding ◽  
Root Cause ◽  
Transmission Electron ◽  
Defect Isolation

Abstract When failure analysis is performed on a circuit composed of FinFETs, the degree of defect isolation, in some cases, requires isolation to the fin level inside the problematic FinFET for complete understanding of root cause. This work shows successful application of electron beam alteration of current flow combined with nanoprobing for precise isolation of a defect down to fin level. To understand the mechanism of the leakage, transmission electron microscopy (TEM) slice was made along the leaky drain contact (perpendicular to fin direction) by focused ion beam thinning and lift-out. TEM image shows contact and fin. Stacking fault was found in the body of the silicon fin highlighted by the technique described in this paper.

scholarly journals Reproductive biology, embryonic development and matrotrophy in the phylactolaemate bryozoan Plumatella casmiana

2021 ◽  
Author(s):  
Julian Bibermair ◽  
Andrew N. Ostrovsky ◽  
Andreas Wanninger ◽  
Thomas Schwaha
Keyword(s):  
Embryonic Development ◽  
Embryo Sac ◽  
The Body ◽  
Transcellular Transport ◽  
Cell Contacts ◽  
Transmission Electron ◽  
Distal Side ◽  
Early Embryos ◽  
Mesoderm Formation ◽  
Cytoplasmic Processes

AbstractBryozoa is a phylum of aquatic, colonial suspension-feeders within the Lophotrochozoa. In the Phylactolaemata embryonic development occurs in an internal brood sac on the body wall accompanied by extraembryonic nutrition. Owing to previous contradictive descriptions, many aspects of their sexual reproduction require restudy. Consequently, this study analyses embryogenesis of the freshwater bryozoan Plumatella casmiana by serial sections, 3D reconstruction and transmission electron microscopy. Early embryos cleave and soon develop into blastulae with a small central cavity. The mesoderm forms by delamination starting from the distal side towards the proximal end. In later embryos two polypides form on the posterior side that ultimately will be covered by a ciliated mantle in the larva. Embryos increase in size during development and form temporary cell contacts to the embryo sac. Mesodermal cells of the embryo sac show signs of transcellular transport indicating that embryos are nourished by transferring nutrients from the maternal coelom towards the brood cavity. This study clarifies several details such as mesoderm formation and the onset of bud development. Embryos are connected to their respective embryo sacs by a variety of temporary cytoplasmic processes formed by both tissues during embryogenesis, including a ‘placental’ ring zone. Although ultrastructural data of these cell contacts are not entirely conclusive about their function, we suggest that embryos absorb nutrients via the entire surface. The close opposition of embryos to the embryo sac implies placentation as matrotrophic mode in phylactolaemate bryozoans, with embryo sacs acting as placental analogues.

scholarly journals A Study of Thin Film Resistors Prepared Using Ni-Cr-Si-Al-Ta High Entropy Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ruei-Cheng Lin ◽  
Tai-Kuang Lee ◽  
Der-Ho Wu ◽  
Ying-Chieh Lee
Keyword(s):  
Annealing Temperature ◽  
Phase Evolution ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Temperature Coefficient Of Resistance ◽  
X Ray ◽  
High Entropy ◽  
Transmission Electron ◽  
Thin Film Resistors

Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 μΩ-cm with −10 ppm/°C of temperature coefficient of resistance (TCR).

Sign in / Sign up

Export Citation Format

Share Document