Anomalous Resistance Behaviour in Non-Superconducting Y–Ba–Cu–O at High Pressures.

1987 ◽  
Vol 01 (03n04) ◽  
pp. 1145-1156
Author(s):  
V. Sankara Sastry ◽  
S. Kalavathi ◽  
B.K. Guha ◽  
R. Baskaran ◽  
U. De ◽  
...  
Keyword(s):  
Layered Structure ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
High Pressures ◽  
Oxide Superconductors ◽  
Electrical Resistance Measurements

Electrical resistance measurements at low temperatures and high quasihydrostatic pressures on superconducting and non-superconducting varieties of Y0.8Ba1.2Cu2O5 (obtained by annealing in oxygen. and air respectively) show striking anomalies in the vicinity of 100K and 40K. Arguments are presented to show that these anomalies as also the occurrence of Tc’s in the oxide superconductors in the vicinity of 100K or of 40K are connected with their layered structure containing planes of Cu–O octahedral complexes.

Low temperature amorphization and superconductivity in FeSe single crystals at high pressures

2010 ◽  
Vol 25 (2) ◽  
pp. 396-400 ◽  
Author(s):  
Andrew K. Stemshorn ◽  
Georgiy Tsoi ◽  
Yogesh K. Vohra ◽  
Stanislav Sinogeiken ◽  
Phillip M. Wu ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Single Crystals ◽  
Amorphous Phase ◽  
Tetragonal Phase ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

In this study, we report low temperature x-ray diffraction studies combined with electrical resistance measurements on single crystals of iron-based layered superconductor FeSe to a temperature of 10 K and a pressure of 44 GPa. The low temperature high pressure x-ray diffraction studies were performed using a synchrotron source and superconductivity at high pressure was studied using designer diamond anvils. At ambient temperature, the FeSe sample shows a phase transformation from a PbO-type tetragonal phase to a NiAs-type hexagonal phase at 10 ± 2 GPa. On cooling, a structural distortion from a PbO-type tetragonal phase to an orthorhombic Cmma phase is observed below 100 K. At a low temperature of 10 K, compression of the orthorhombic Cmma phase results in a gradual transformation to an amorphous phase above 15 GPa. The transformation to the amorphous phase is completed by 40 GPa at 10 K. A loss of superconductivity is observed in the amorphous phase and a dramatic change in the temperature behavior of electrical resistance indicates formation of a semiconducting state at high pressures and low temperatures. The formation of the amorphous phase is attributed to a kinetic hindrance to the growth of a hexagonal NiAs phase under high pressures and low temperatures.

Electrical resistance measurements on young balsam fir trees in relation to specific volume increment, foliar biomass, and ion content of bark and wood

1984 ◽  
Vol 14 (2) ◽  
pp. 177-180 ◽  
Author(s):  
H. Plene ◽  
R. G. Thompson ◽  
J. E. McIsaac ◽  
D. S. Fensom
Keyword(s):  
Electrical Resistance ◽  
Specific Volume ◽  
Balsam Fir ◽  
Ion Content ◽  
Volume Increment ◽  
Electrical Resistance Measurements ◽  
Foliar Biomass

Electrical resistance in young balsam fir (Abiesbalsamea (L.) Mill.) trees was inversely (nonlinear) correlated with specific volume increment, total foliar biomass, and the combined weight of the current and 1-year-old foliage. These relationships were stronger before budbreak than after. No relationship existed between concentrations of N, P, K, Ca, and Mg in the bark and wood collected around time of budbreak, and electrical resistance.

Effects of ultra-high pressures (>3.6 GPa) on the electrical resistance of polyaniline by in situ FT-IR studies

1997 ◽  
Vol 280 (5-6) ◽  
pp. 469-474 ◽  
Author(s):  
Xing-Rong Zeng ◽  
Ke-Cheng Gong ◽  
Ke-Nan Weng ◽  
Wan-Sheng Xiao ◽  
Wen-Hong Gan ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
High Pressures ◽  
Ir Studies ◽  
Ft Ir
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