Sound Velocity and Ultrasonic Absorption in High-Tc-Superconductors

1987 ◽  
Vol 26 (S3-3) ◽  
pp. 2139 ◽  
Author(s):  
V. Müller ◽  
K. de Groot ◽  
D. Maurer ◽  
Ch. Roth ◽  
K. H. Rieder ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Ultrasonic Absorption ◽  
High Tc Superconductors ◽  
High Tc

Effect of magnetic field on the sound velocity discontinuity near Tc in high Tc superconductors

1990 ◽  
Vol 166 (1-2) ◽  
pp. 87-94 ◽  
Author(s):  
Yuuji Horie ◽  
Yuichiro Terashi ◽  
Takeshi Fukami ◽  
Shoichi Mase
Keyword(s):  
Magnetic Field ◽  
Sound Velocity ◽  
High Tc Superconductors ◽  
High Tc ◽  
Velocity Discontinuity

The many faces of STEM in materials science

1991 ◽  
Vol 49 ◽  
pp. 440-441
Author(s):  
John Silcox
Keyword(s):  
Materials Science ◽  
Auger Spectroscopy ◽  
Dark Field ◽  
High Tc Superconductors ◽  
High Tc ◽  
Acoustic Environment ◽  
Electromagnetic Vibration ◽  
The Many ◽  
Serial Mode

Determination of the microstructure and microchemistry of small features often provides the insight needed for the understanding of processes in real materials. In many cases, it is not adequate to use microscopy alone. Microdiffraction and microspectroscopic information such as EELS, X-ray microprobe analysis and Auger spectroscopy can all contribute vital parts of the picture. For a number of reasons, dedicated STEM offers considerable promise as a quantitative instrument. In this paper, we review progress towards effective quantitative use of STEM with illustrations drawn from studies of high Tc superconductors, compound semiconductors and metallization of H-terminated silicon.Intrinsically, STEM is a quantitative instrument. Images are acquired directly by detectors in serial mode which is particularly convenient for digital image acquisition, control and display. The VG HB501A at Cornell has been installed in a particularly stable electromagnetic, vibration and acoustic environment. Care has been paid to achieving UHV conditions (i.e., 10-10 Torr). Finally, it has been interfaced with a VAX 3200 work station by Kirkland. This permits, for example, the acquisition of bright field (or energy loss) images and dark field images simultaneously as quantitative arrays in perfect registration.

Crystal chemistry of high-Tc superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 1118-1119
Author(s):  
Maryvonne Hervieu
Keyword(s):  
Oxygen Deficiency ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc ◽  
Single Mechanism ◽  
Square Planar ◽  
History Of ◽  
Bismuth Cuprates ◽  
New Compounds

Four years after the discovery of superconductivity at high temperature in the Ba-La-Cu-O system, more than thirty new compounds have been synthesized, which can be classified in six series of copper oxides: La2CuO4 - type oxides, bismuth cuprates, YBa2Cu3O7 family, thallium cuprates, lead cuprates and Nd2CuO4 - type oxides. Despite their quite different specific natures, close relationships allow their structures to be simply described through a single mechanism. The fifth first families can indeed be described as intergrowths of multiple oxygen deficient perovskite slabs with multiple rock salt-type slabs, according to the representation [ACuO3-x]m [AO]n.The n and m values are integer in the parent structures, n varying from 0 to 3 and m from 1 to 4; every member of this large family can thus be symbolized by [m,n]. The oxygen deficient character of the perovskite slabs involves the existence or the co-existence of several types of copper environment: octahedral, pyramidal and square planar.Both mechanisms, oxygen deficiency and intergrowth, are well known to give rise easily to nonstoichiometry phenomena. Numerous and various phenomena have actually been characterized in these cuprates, strongly depending on the thermal history of the samples.

Anisotropic Vortex Dynamics Related to Screening Currents and Microwave Currents under Magnetic Fields on High Tc Superconductors

PIERS Online ◽  
2005 ◽  
Vol 1 (1) ◽  
pp. 110-114
Author(s):  
Tamio Endo ◽  
Hong Zhu ◽  
Takahisa Sakurada ◽  
Ajay K. Sarkar ◽  
Masanori Okada ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Vortex Dynamics ◽  
High Tc Superconductors ◽  
High Tc
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