The identification of single-domain titanomagnetite particles by means of transmission electron microscopy

1979 ◽  
Vol 16 (2) ◽  
pp. 375-379 ◽  
Author(s):  
P. P. K. Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Remanent Magnetization ◽  
Magnetic Domain ◽  
Natural Remanent Magnetization ◽  
Small Particles ◽  
Dispersed Particles ◽  
Transmission Electron ◽  
Mid Atlantic Ridge ◽  
Means Of Transmission

A basalt sample dredged from the axis of the Mid-Atlantic Ridge has been ion-thinned and examined by transmission electron microscopy. Finely dispersed particles as small as 0.04 μm in diameter, occurring in amorphous patches of the rock, have been identified as titanomagnetite by means of electron diffraction and microanalysis. These small particles have dimensions appropriate to single magnetic domain behaviour, and are considered to be largely responsible for the strong and very stable natural remanent magnetization of this rock.

DEFECTS OF A15 SMALL PARTICLES IN TUNGSTEN THIN FILMS

1996 ◽  
Vol 03 (01) ◽  
pp. 1191-1194 ◽  
Author(s):  
MASASHI ARITA ◽  
ISAO NISHIDA
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Crystal Defects ◽  
Type Structure ◽  
Special Structure ◽  
Small Particles ◽  
Structure Unit ◽  
Transmission Electron ◽  
Means Of Transmission

Crystal defects of A15 small particles in tungsten thin films were studied by means of transmission electron microscopy. Defects found in nanoscale crystals were analyzed to have special structure containing the Zr4Al3-type structure unit.

Microtexture of shock reaction products of niobium and silica mixtures

1999 ◽  
Vol 14 (7) ◽  
pp. 3169-3174 ◽  
Author(s):  
Reiko Murao ◽  
Masae Kikuchi ◽  
Kiyoto Fukuoka ◽  
Eiji Aoyagi ◽  
Toshiyuki Atou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Shock Compression ◽  
Pressure Range ◽  
Reaction Products ◽  
Small Particles ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron

Shock compression experiments on powder mixtures of niobium metal and quartz were conducted for the pressure range of 30–40 GPa by a 25-mm single-stage propellant gun. Chemical reaction occurred above 35 GPa, and products were found to be mainly so-called “Cu3Au-type” Nb3Si, which contained a small amount of oxygen. Microtextures of the specimen were examined by scanning and transmission electron microscopy. A field-emission transmission electron microscope was used for energy-dispersive x-ray analysis of microtextures in small particles found in the SiO2 matrix, and various species with different Nb/Si ratio and oxygen content were shown to be produced through the nonequilibrium process of shock compression.

Structural Properties of Amorphous Silicon Produced by Electron Irradiation

1999 ◽  
Vol 557 ◽  
Author(s):  
J. Yamasaki ◽  
S. Takeda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Distribution Function ◽  
Structural Properties ◽  
Electron Irradiation ◽  
Low Temperatures ◽  
Crystalline Silicon ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Means Of Transmission

AbstractThe structural properties of the amorphous Si (a-Si), which was created from crystalline silicon by 2 MeV electron irradiation at low temperatures about 25 K, are examined in detail by means of transmission electron microscopy and transmission electron diffraction. The peak positions in the radial distribution function (RDF) of the a-Si correspond well to those of a-Si fabricated by other techniques. The electron-irradiation-induced a-Si returns to crystalline Si after annealing at 550°C.

scholarly journals The Transport System of Nacre Components through the Surface Membrane of Gastropods

2016 ◽  
Vol 672 ◽  
pp. 103-112 ◽  
Author(s):  
Elena Macías-Sánchez ◽  
Antonio G. Checa ◽  
Marc G. Willinger
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Calcium Carbonate ◽  
Lamellar Structure ◽  
Surface Membrane ◽  
Organic Matrix ◽  
X Ray ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Electron Energy Loss

The surface membrane is a lamellar structure exclusive of gastropods that is formed during the shell secretion. It protects the surface of the growing nacre and it is located between the mantle epithelium and the mineralization compartment. At the mantle side of the surface membrane numerous vesicles provide material, and at the nacre side, the interlamellar membranes detach from the whole structure. Components of nacre (glycoproteins, polysaccharides and calcium carbonate) cross the structure to reach the mineralization compartment, but the mechanism by which this occurs is still unknown. In this paper we have investigated the ultrastructure of the surface membrane and the associated vesicle layer by means of Transmission Electron Microscopy. Electron Energy Loss Spectroscopy and Energy-dispersive X-ray Spectroscopy were used for elemental analysis. The analyses revealed the concentration of calcium in the studied structures: vesicles, surface membrane, and interlamellar membranes. We discuss the possible linkage of calcium to the organic matrix.

Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

2003 ◽  
Vol 779 ◽  
Author(s):  
Hyung Seok Kim ◽  
Sang Ho Oh ◽  
Ju Hyung Suh ◽  
Chan Gyung Park
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

scholarly journals Secondary magnetite in ancient zircon precludes analysis of a Hadean geodynamo

2018 ◽  
Vol 116 (2) ◽  
pp. 407-412 ◽  
Author(s):  
Fengzai Tang ◽  
Richard J. M. Taylor ◽  
Josh F. Einsle ◽  
Cauê S. Borlina ◽  
Roger R. Fu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Remanent Magnetization ◽  
Diffusion Mechanism ◽  
Aqueous Fluid ◽  
Pipe Diffusion ◽  
Transmission Electron ◽  
Igneous Zircon ◽  
Jack Hills ◽  
Magnetic Inclusions

Zircon crystals from the Jack Hills, Western Australia, are one of the few surviving mineralogical records of Earth’s first 500 million years and have been proposed to contain a paleomagnetic record of the Hadean geodynamo. A prerequisite for the preservation of Hadean magnetization is the presence of primary magnetic inclusions within pristine igneous zircon. To date no images of the magnetic recorders within ancient zircon have been presented. Here we use high-resolution transmission electron microscopy to demonstrate that all observed inclusions are secondary features formed via two distinct mechanisms. Magnetite is produced via a pipe-diffusion mechanism whereby iron diffuses into radiation-damaged zircon along the cores of dislocations and is precipitated inside nanopores and also during low-temperature recrystallization of radiation-damaged zircon in the presence of an aqueous fluid. Although these magnetites can be recognized as secondary using transmission electron microscopy, they otherwise occur in regions that are indistinguishable from pristine igneous zircon and carry remanent magnetization that postdates the crystallization age by at least several hundred million years. Without microscopic evidence ruling out secondary magnetite, the paleomagnetic case for a Hadean–Eoarchean geodynamo cannot yet been made.

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