Temperature dependence of the surface resistance R(T,ω) and mean free path l(T) of YBCO-superconductors

1997 ◽  
Vol 7 (2) ◽  
pp. 1917-1920 ◽  
Author(s):  
T. Jacobs ◽  
K. Numssen ◽  
R. Schwab ◽  
R. Heidinger ◽  
J. Halbritter
Keyword(s):  
Temperature Dependence ◽  
Free Path ◽  
Surface Resistance ◽  
Mean Free Path ◽  
Ybco Superconductors

scholarly journals Temperature Dependence of the Hall Coefficient of Thin Films

1979 ◽  
Vol 6 (1) ◽  
pp. 19-22
Author(s):  
C. R. Tellier ◽  
C. Pichard ◽  
A. J. Tosser
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Theoretical Expression ◽  
Metallic Films ◽  
Conduction Model ◽  
The Mean

A theoretical expression for the temperature coefficientβRHof the Hall coefficientRHFof metallic films is deduced from the Fuchs–Sondheimer conduction model. The general expression takes into account the deviation introduced by the geometrical limitation of the mean free path. This is negligible for relatively thick films (k≥ 1 forp= 0) and agrees with experiments previously reported by other authors.

Synthesis and Thermoelectric Properties of NaxCo2O4 Single Crystals

2005 ◽  
Vol 886 ◽  
Author(s):  
Jian He ◽  
Kelvin Aaron ◽  
Edward Abbott ◽  
Joseph Kolis ◽  
Terry M. Tritt
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Low Temperature ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Free Path ◽  
Mean Free Path ◽  
Flux Method ◽  
Different Types

ABSTRACTSingle crystal NaCo2O4 platelets with sizes up to 6mm were synthesized by the typical high temperature NaCl flux method. The in-plane thermopower α and in-plane resistivity ρ were measured to be ∼100µV/K and 0.3mΩ-cm at 300K, respectively. The in-plane thermal conductivity κ was measured by our custom-designed “PTC” system and found to be ∼5 W-m−1K−1 at 300K, which is 2-3 times larger than the polycrystalline NaCo2O4. The in-plane phonon mean free path lph was estimated to be ∼9.5Å, which is much smaller than the in-plane mean free path of conducting carriers (la∼51Å). A novel low temperature flux method where NaCl/NaOH was used as flux and metallic Co powders as Co source was developed to successfully synthesize Na-deficient NaxCo2O4 crystals with size up to 6mm at low temperature of 550°C. The different temperature dependence in resistivity reveals that two different types of crystals can exist, one is metallic and another is semiconducting. The temperature dependence of the measured k is like that of a disordered solid and the value is found to be ∼7 W-m−1K−1 at 300K.

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