scholarly journals Flux pinning mechanism in BaFe1.9Ni0.1As2 single crystals: Evidence for fluctuation in mean free path induced pinning

2013 ◽  
Vol 103 (3) ◽  
pp. 032605 ◽  
Author(s):  
M. Shahbazi ◽  
X. L. Wang ◽  
K. Y. Choi ◽  
S. X. Dou
Keyword(s):  
Single Crystals ◽  
Free Path ◽  
Flux Pinning ◽  
Mean Free Path ◽  
Pinning Mechanism

scholarly journals Flux-pinning mechanism in silicone-oil-dopedMgB2: Evidence for charge-carrier mean free path fluctuation pinning

2008 ◽  
Vol 78 (18) ◽  
Author(s):  
S. R. Ghorbani ◽  
X. L. Wang ◽  
S. X. Dou ◽  
Sung-IK Lee ◽  
M. S. A. Hossain
Keyword(s):  
Charge Carrier ◽  
Free Path ◽  
Flux Pinning ◽  
Silicone Oil ◽  
Mean Free Path ◽  
Pinning Mechanism

Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals

2021 ◽  
Author(s):  
Yongqiang Pan ◽  
Nan Zhou ◽  
Bencheng Lin ◽  
Jinhua Wang ◽  
Zengwei Zhu ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Pinning Force ◽  
Magnetization Relaxation ◽  
Pinning Mechanism

Abstract Fe1+yTe0.6Se0.4 has considerable application potential due to its large critical current density (J c) and high upper critical magnetic field (H c2). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c ab /J c c ~ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities (F p) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p[F p/F p-max] versus the normalized field h[H/H c2]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe1+yTe0.6Se0.4 clean single crystals was confirmed to be normal point pinning.

Thermal Conductivity of Single-Crystal and Sintered RBa2Cu3O7 at low Temperatures

1987 ◽  
Vol 99 ◽  
Author(s):  
J. E. Graebner ◽  
L. F. Schneemeyer ◽  
R. J. Cava ◽  
J. V. Waszczak ◽  
E. A. Rietman
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Single Crystals ◽  
Free Path ◽  
Low Temperatures ◽  
Rayleigh Scattering ◽  
Resonant Scattering ◽  
Sintered Sample ◽  
Mean Free Path ◽  
Strong Scattering

ABSTRACTThe thermal conductivity k of micro-twinned single crystals of YBa2Cu3O7 and HoBa2Cu3O7 and a sintered sample of YBa2Cu3O7 has been measured for temperatures 0.03<T<5K. For the single crystals, k is small and varies as T1.8-1.9 This behavior resembles k for glassy insulators except for the lack of a plateau above IK. It is concluded that the thermal carriers are phonons with their mean free path limited by resonant scattering from tunneling entities, as in glasses. Suggestions for the location of tunneling systems are given. For the sinter, k is still smaller but does not follow a power law T-dependence. It is similar to other sintered ceramics with the same particle size, where the phonon mean free path is dominated by Rayleigh scattering from the particles. This strong scattering from the microstructure presumably masks the scattering from TS within each particle.

The mean free path of mobile dislocations in doped NaCl single crystals measured by N.M.R. between room temperature and 300°C

1982 ◽  
Vol 46 (3) ◽  
pp. 469-481 ◽  
Author(s):  
W. H. M. Alsem ◽  
J. Th. M. De Hosson ◽  
R. Muenter ◽  
H. Tamler ◽  
O. Kanert
Keyword(s):  
Single Crystals ◽  
Free Path ◽  
Room Temperature ◽  
Mean Free Path ◽  
The Mean

scholarly journals Study of flux pinning mechanism under hydrostatic pressure in optimally doped (Ba,K)Fe2As2 single crystals

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Babar Shabbir ◽  
Xiaolin Wang ◽  
Y. Ma ◽  
S. X. Dou ◽  
S. S. Yan ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Single Crystals ◽  
Flux Pinning ◽  
Pinning Mechanism

scholarly journals Thermal Conductivity of Gel-Grown Barium Oxalate at 326 and 335 K

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Paresh Vasantlal Dalal
Keyword(s):  
Thermal Conductivity ◽  
Ambient Temperature ◽  
Single Crystals ◽  
Free Path ◽  
Grown Crystal ◽  
Mean Free Path ◽  
Monoclinic Structure ◽  
Agar Gel ◽  
Gel Method ◽  
Barium Oxalate

Single crystals of barium oxalate have been grown by gel method using agar-agar gel as media of growth at ambient temperature. The grown crystal crystallizes under monoclinic structure. Thermal conductivity of gel-grown barium oxalate crystals as a function of temperature has been studied at 326 and 335 K by using divided bar method. The thermal conductivity of barium oxalate crystal at 326 K was found 3.685 W m−1 K−1 and 3.133 W m−1 K−1 at 335 K. The reduction of thermal conductivity with the rise in temperature may be due to reduction in mean free path of phonons in the solid.

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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