Positron annihilation in fatigued copper

1982 ◽  
Vol 60 (2) ◽  
pp. 201-204 ◽  
Author(s):  
S. Kupca ◽  
D. P. Kerr ◽  
B. G. Hogg ◽  
Z. S. Basinski
Keyword(s):  
Single Crystals ◽  
Point Defects ◽  
High Purity ◽  
Low Temperatures ◽  
Annealing Process ◽  
Simple Diffusion ◽  
Diffusion Limited ◽  
Annealing Study ◽  
Positron Lifetimes ◽  
Trapping Process

Positron lifetimes have been measured in an isochronal annealing study of dynamically fatigued, high purity Cu single crystals. Decomposition of the lifetime spectra into two components results in a description of the annealing process in terms of the lifetime and fraction of trapped positrons. Positron lifetimes were also determined at a series of low temperatures (10–300 K) at different stages of annealing. The lifetime of positrons trapped at point defects is found to vary with temperature indicating that a description of the trapping process according to a simple diffusion limited model is not applicable.

scholarly journals Largely improvedJcat low temperatures observed in Y123 single crystals with chemically introduced point defects

2010 ◽  
Vol 234 (1) ◽  
pp. 012018 ◽  
Author(s):  
Y Ishii ◽  
T Akasaka ◽  
Y Kinemura ◽  
H Ogino ◽  
S Horii ◽  
...  
Keyword(s):  
Single Crystals ◽  
Point Defects ◽  
Low Temperatures

Effect of Point Defects on the Character of Distortions in High-Purity Molybdenum Single Crystals

1986 ◽  
Vol 98 (2) ◽  
pp. 521-526 ◽  
Author(s):  
I. S. Braude ◽  
U. Hofmann ◽  
H.-J. Kaufmann ◽  
V. I. Startsev
Keyword(s):  
Single Crystals ◽  
Point Defects ◽  
High Purity

Stabilization Effect in BaTiO3 Single Crystal during Aging below Tc

2005 ◽  
Vol 475-479 ◽  
pp. 1169-1172 ◽  
Author(s):  
Da Zhi Sun ◽  
Xiao Bing Ren ◽  
Shi Ping Yang ◽  
Hao Su Luo ◽  
Kazuhiro Otsuka
Keyword(s):  
Differential Scanning Calorimetry ◽  
Curie Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Point Defects ◽  
High Purity ◽  
Ferroelectric Phase ◽  
Reverse Transformation ◽  
Scanning Calorimetry ◽  
Stabilization Effect

High purity BaTiO3 single crystal was aged below its Curie temperature for different times. The reverse transformation (from tetragonal to cubic) temperature was measured precisely by differential scanning calorimetry (DSC). It was observed that the reverse transformation temperature increased with increasing aging time, indicating ferroelectric phase became stable with aging. This behavior is the same as found in ferroelastic alloys. The origin of the stabilization effect in ferroelectric single crystals was discussed with respect to the distribution of point defects.

The thermal conductivity of metals at low temperatures

1955 ◽  
Vol 247 (933) ◽  
pp. 441-497 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Single Crystals ◽  
High Purity ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Lorenz Number ◽  
Normal States ◽  
Full Temperature ◽  
Limiting Value

The thermal conductivity of high-purity samples of thirty-two metals has been measured. These were Ag, Al, Au, Be, Cb, Cd, Ce, Co, Cu, Fe, Ga, In, Ir, La, Mg, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Sb, Sn, Ta, Ti, Tl, U, V, W, Zn and Zr. For most metals measurements were taken from 2 to 40°K, but where necessary they were extended to 90°K. For superconductors they were taken in both the superconducting and normal states. The conductivity was found to be entirely electronic except for Sb and U. Most of the specimens were polycrystalline, but single crystals of Zn, Cd, Sn, Pb, Ga and Ti were measured. For Zn and Ga, specimens of different orientations with respect to the rod axis were obtained, and in both these metals the thermal conductivity was found to be anisotropic. The thermal resistance, W, at low temperatures of nearly all the metals is of the form W — a T 2 + gjT, and the constants a and /? have been calculated. If is the limiting thermal conductivity at high temperatures and 6 is the Debye temperature, then the value of aK^d2 is the same for the metals in any one chemical group. For some metals the electrical resistance was measured at the same time as the thermal conductivity over the full temperature range and hence the Lorenz number, L, was calculated. The limiting value of L at low temperatures for several metals was found to be considerably higher than the theoretical value, in particular for Ti and Zr. A corresponding effect to the minimum in the electrical resistance of Mg has been found in the thermal resistance. A large increase in the thermal conductivity of Fe after a period of time has been ascribed to the precipitation of impurities in the metal. A method is given for estimating the thermal conductivity of a metal at low temperatures.

DISLOCATION RELAXATION PEAKS IN HIGH PURITY TUNGSTEN SINGLE CRYSTALS

1983 ◽  
Vol 44 (C9) ◽  
pp. C9-691-C9-696 ◽  
Author(s):  
U. Ziebart ◽  
H. Schultz
Keyword(s):  
Single Crystals ◽  
High Purity

Effect of Mn3+ doping on crystal structure, point defects, and optical properties in green Ca3(VO4)2 single crystals

2021 ◽  
pp. 111300
Author(s):  
Galina M. Kuz’micheva ◽  
Liudmila. I. Ivleva ◽  
Irina A. Kaurova ◽  
Evgeny V. Khramov ◽  
Victor B. Rybakov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Single Crystals ◽  
Point Defects
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