THERMAL CONDUCTIVITY OF YBa2Cu3O7: s-WAVE INTERPRETATION

2005 ◽  
Vol 19 (01n03) ◽  
pp. 147-151 ◽  
Author(s):  
DALE R. HARSHMAN ◽  
JOHN D. DOW
Keyword(s):  
Thermal Conductivity ◽  
High Temperature Superconductor ◽  
Wave Model ◽  
Zero Field ◽  
Conductivity Data ◽  
S Wave ◽  
Specific Heat Data ◽  
Thermal Conductivity Data ◽  
D Wave ◽  
Heat Data

Previous interpretations of the thermal conductivity data of YBa 2 Cu 3 O 7 in terms of d-wave superconductivity have created the impression that this experiment can only be successfully explained in terms of a d-wave model. Here we show that thermal conductivity data can be (better) explained in terms of s-wave hole-pairing, which also handles some outstanding problems with the d-wave interpretation, namely, muon spectra that are s-wave and specific heat data that exhibit a zero-field linear-T term. The basic notion is that a high-temperature superconductor such as YBa 2 Cu 2 O 7 contains both superconducting and non-superconducting bands. The main superconducting bands are associated with BaO , and the CuO 2 bands are non-superconducting.

scholarly journals PROTON MAGNETIC RESONANCE IN PARAMAGNETIC AND ANTIFERROMAGNETIC CoCl2∙6H2O

1964 ◽  
Vol 42 (4) ◽  
pp. 657-677 ◽  
Author(s):  
E. Sawatzky ◽  
M. Bloom
Keyword(s):  
Magnetic Resonance ◽  
Crystal Orientation ◽  
Applied Field ◽  
Field Approximation ◽  
Order Effects ◽  
Zero Field ◽  
Proton Resonance ◽  
Specific Heat Data ◽  
Thermodynamic Variables ◽  
Heat Data

The transition temperature TN of CoCl2∙6H2O was measured as a function of applied field and crystal orientation using the proton resonance lines, since they are very sensitive functions of temperature near TN. TN was found to be a complicated function of the applied field and crystal orientation, which cannot be described by the molecular field approximation. The transition is gradual rather than sudden and coexistence of the NMR spectra associated with the paramagnetic and antiferromagnetic phases was observed over a temperature region of about 10−2 °K. Short-range order effects were observed near TN in the form of anomalous broadening of the magnetic resonance lines. The magnetic susceptibility in zero field was measured along the preferred axis of antiferromagnetic alignment. This, together with specific heat data from published literature, was used to show a mutual consistency between thermodynamic variables and the dependence of TN on H in low fields as obtained by NMR. The treatment follows that of Buckingham and Fairbank for the λ transition in liquid helium. The sublattice magnetization in the antiferromagnetic phase was measured as a function of temperature. It was found to depend logarithmically on (TN – T), for all values of applied field.

Thermal conductivity data for refrigerant mixtures containing R1234yf and R1234ze(E)

2019 ◽  
Vol 133 ◽  
pp. 135-142 ◽  
Author(s):  
Sofia K. Mylona ◽  
Thomas J. Hughes ◽  
Amina A. Saeed ◽  
Darren Rowland ◽  
Juwoon Park ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Data ◽  
Thermal Conductivity Data ◽  
Refrigerant Mixtures

A Review of Thermal Conductivity Data, Mechanisms and Models for Nanofluids

2010 ◽  
Vol 1 (4) ◽  
pp. 269-322 ◽  
Author(s):  
Ji-Hwan Lee ◽  
Seung-Hyun Lee ◽  
Chul Choi ◽  
Seok Jang ◽  
Stephen Choi
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Data ◽  
Thermal Conductivity Data

Estimating thermal diffusivity and specific heat from needle probe thermal conductivity data

2006 ◽  
Vol 77 (4) ◽  
pp. 044904 ◽  
Author(s):  
William F. Waite ◽  
Lauren Y. Gilbert ◽  
William J. Winters ◽  
David H. Mason
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Conductivity Data ◽  
Thermal Conductivity Data ◽  
Needle Probe

Specific models for estimation of locally oriented laboratory thermal conductivity of tertiary sediments in the Niger Delta using wire line logs

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Akpabio Thompson ◽  
George Jimmy ◽  
Udofia Michael
Keyword(s):  
Thermal Conductivity ◽  
Niger Delta ◽  
Empirical Models ◽  
High Fidelity ◽  
Conductivity Data ◽  
Formation Factor ◽  
Model Based ◽  
Thermal Conductivity Data ◽  
Bed Thickness ◽  
Cementation Factor

AbstractIn this study, specific development of empirical models for estimation of laboratory thermal conductivities from wire line log thermal conductivity within the ambience of locally oriented wells located in the Niger Delta have been established. The laboratory thermal conductivity is characterised with high fidelity compared to wire line log thermal conductivity whose values vary as the dependence of lithology of the subsurface geomaterials, well effects, as well as the effects of the limited bed thickness of the adjacent lithological units of the Niger Delta where the study was stationed. The generalised equation kleff = 0.709 kweff + 0.188 is an empirically estimated model based on site variables (porosity, permeability and temperature) and constants (cementation factor, formation factor and tortuosity) of the locally oriented wells in the Niger Delta. It can be used to set bounds on the unstable wire line log thermal conductivity values within the 1-2.5 km depths where the oil-rich geomaterials in the Niger Delta are usually found. Equations have been established which show inter-convertibility between laboratory and wire line log thermal conductivity. These equations are considered useful in converting the available wire line log thermal conductivity data of nearby wells in the area to the usually desired and stable laboratory thermal conductivity. Various diagrams in 2-D and 3-D have been established to show the distribution of the parameters considered, and this could help the operating companies in the zone to predict the density of oil.

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