scholarly journals Influence of magnetic field on electrical and thermal transport in the hole doped ferromagnetic manganite: La0.9Na0.1MnO3

RSC Advances ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 1726-1733 ◽  
Author(s):  
Rajasree Das ◽  
Amit Chanda ◽  
Ramanathan Mahendiran
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermal Transport ◽  
Field Dependent

Magnetic field dependent electrical resistivity (ρ), thermal conductivity (κ) and thermopower (S) of polycrystalline La0.9Na0.1MnO3 have been reported and the possible mechanisms are discussed.

Effect of magnetic field-dependent thermal conductivity on natural convection of magnetic nanofluid inside a square enclosure

2019 ◽  
Vol 29 (4) ◽  
pp. 1466-1489 ◽  
Author(s):  
Mohammadhossein Hajiyan ◽  
Shohel Mahmud ◽  
Mohammad Biglarbegian ◽  
Hussein A. Abdullah ◽  
A. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Hartmann Number ◽  
Magnetic Nanofluid ◽  
Content Type ◽  
Square Enclosure ◽  
Field Dependent

Purpose The purpose of this paper is to investigate the convective heat transfer of magnetic nanofluid (MNF) inside a square enclosure under uniform magnetic fields considering nonlinearity of magnetic field-dependent thermal conductivity. Design/methodology/approach The properties of the MNF (Fe3O4+kerosene) were described by polynomial functions of magnetic field-dependent thermal conductivity. The effect of the transverse magnetic field (0 < H < 105), Hartmann Number (0 < Ha < 60), Rayleigh number (10 <Ra <105) and the solid volume fraction (0 < φ < 4.7%) on the heat transfer performance inside the enclosed space was examined. Continuity, momentum and energy equations were solved using the finite element method. Findings The results show that the Nusselt number increases when the Rayleigh number increases. In contrast, the convective heat transfer rate decreases when the Hartmann number increases due to the strong magnetic field which suppresses the buoyancy force. Also, a significant improvement in the heat transfer rate is observed when the magnetic field is applied and φ = 4.7% (I = 11.90%, I = 16.73%, I = 10.07% and I = 12.70%). Research limitations/implications The present numerical study was carried out for a steady, laminar and two-dimensional flow inside the square enclosure. Also, properties of the MNF are assumed to be constant (except thermal conductivity) under magnetic field. Practical implications The results can be used in thermal storage and cooling of electronic devices such as lithium-ion batteries during charging and discharging processes. Originality/value The accuracy of results and heat transfer enhancement having magnetic field-field-dependent thermal conductivity are noticeable. The results can be used for different applications to improve the heat transfer rate and enhance the efficiency of a system.

Effect of electron inertia on radiative instability of rotating two-component gaseous plasma

2012 ◽  
Vol 90 (12) ◽  
pp. 1209-1221 ◽  
Author(s):  
A.K. Patidar ◽  
R.K. Pensia ◽  
V. Shrivastava
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Growth Rate ◽  
Electrical Resistivity ◽  
Heat Loss ◽  
Loss Function ◽  
Mode Analysis ◽  
Electron Inertia ◽  
Radiative Instability ◽  
Jeans Criterion

The problem of radiative instability of homogeneous rotating partially ionized plasma incorporating viscosity, porosity, and electron inertia in the presence of a magnetic field is investigated. A general dispersion relation is obtained using normal mode analysis with the help of relevant linearized perturbation equations of the problem. The modified Jeans criterion of instability is obtained. The conditions of Jeans instabilities are discussed in the different cases of interest. It is found that the simultaneous effect of viscosity, rotation, finite conductivity, and porosity of the medium does not essentially change the Jeans criterion of instability. It is also found that the presence of arbitrary radiative heat-loss function and thermal conductivity modified the conditions of Jeans instability for longitudinal propagation. It is found that, for longitudinal propagation, the conditions of radiative instability are independent of magnetic field, viscosity, rotation, finite electrical resistivity, and electron inertia, but for the transverse mode of propagation it depends upon finite electrical resistivity and strength of magnetic field and is independent of viscosity, electron inertia, and rotation. From the curves we find that viscosity has a stabilizing effect on the growth rate of instability but the thermal conductivity and density-dependent heat-loss function has a destabilizing effect on the instability growth rate.

scholarly journals Thermal transport properties of decagonal quasicrystals and their approximants

2013 ◽  
Vol 1517 ◽  
Author(s):  
Petar Popčević ◽  
Ante Bilušić ◽  
Kristijan Velebit ◽  
Ana Smontara
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Transport Properties ◽  
Heat Transport ◽  
Thermal Transport ◽  
Strong Relationship ◽  
Decagonal Quasicrystal ◽  
Decagonal Quasicrystals ◽  
Plane Anisotropy ◽  
Out Of Plane

ABSTRACTTransport properties (thermal conductivity, electrical resistivity and thermopower) of decagonal quasicrystal d-AlCoNi, and approximant phases Y-AlCoNi, o-Al13Co4, m-Al13Fe4, m-Al13(Fe,Ni)4 and T-AlMnFe have been reviewed. Among all presented alloys the stacking direction (periodic for decagonal quasicrystals) is the most conductive one for the charge and heat transport, and the in/out-of-plane anisotropy is much larger than the in-plane anisotropy. There is a strong relationship between periodicity length along stacking direction and anisotropy of transport properties in both quasicrystals and their approximants suggesting a decrease of the anisotropy with increasing number of stacking layers.

Annealing Studies of Re Doped AlPdMn Quasicrystals

2001 ◽  
Vol 691 ◽  
Author(s):  
Donny W. Winkler ◽  
Terry M. Tritt ◽  
Robert Gagnon ◽  
J. Strom-Olsen
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Transport Properties ◽  
Thermal Transport ◽  
Amorphous Materials ◽  
Annealed Sample ◽  
Annealing Conditions ◽  
Thermal Transport Properties ◽  
The Relationship

ABSTRACTQuasicrystals have properties associated with both crystalline and amorphous materials. These properties appear to be sensitive to both composition and annealing conditions. Therefore, it is important to investigate the influence of the microstructure on the electrical and thermal transport properties of quasicrystals. AlPdMn quasicrystal samples were prepared with various levels of Re substituted for the Mn (Al70Pd20Mn10−XReX) and then subjected to different annealing conditions. Electrical resistivity, thermopower and thermal conductivity were measured on each as grown and annealed sample over a broad range of temperature, 10 K < T < 300 K. The relationship between the electrical and thermal transport properties and microstructure will be presented and discussed.

scholarly journals Effect of magnetic field on the charge and thermal transport properties of hot and dense QCD matter

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Shubhalaxmi Rath ◽  
Binoy Krishna Patra
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Strong Magnetic Field ◽  
Knudsen Number ◽  
Thermal Transport ◽  
Isotropic Medium ◽  
Chemical Potential ◽  
Lorenz Number

Abstract We have studied the effect of strong magnetic field on the charge and thermal transport properties of hot QCD matter at finite chemical potential. For this purpose, we have calculated the electrical conductivity ($$\sigma _\mathrm{el}$$σel) and the thermal conductivity ($$\kappa $$κ) using kinetic theory in the relaxation time approximation, where the interactions are subsumed through the distribution functions within the quasiparticle model at finite temperature, strong magnetic field and finite chemical potential. This study helps to understand the impacts of strong magnetic field and chemical potential on the local equilibrium by the Knudsen number ($$\Omega $$Ω) through $$\kappa $$κ and on the relative behavior between thermal conductivity and electrical conductivity through the Lorenz number (L) in the Wiedemann–Franz law. We have observed that, both $$\sigma _\mathrm{el}$$σel and $$\kappa $$κ get increased in the presence of strong magnetic field, and the additional presence of chemical potential further increases their magnitudes, where $$\sigma _\mathrm{el}$$σel shows decreasing trend with the temperature, opposite to its increasing behavior in the isotropic medium, whereas $$\kappa $$κ increases slowly with the temperature, contrary to its fast increase in the isotropic medium. The variation in $$\kappa $$κ explains the decrease of the Knudsen number with the increase of the temperature. However, in the presence of strong magnetic field and finite chemical potential, $$\Omega $$Ω gets enhanced and approaches unity, thus, the system may move slightly away from the equilibrium state. The Lorenz number ($$\kappa /(\sigma _\mathrm{el} T))$$κ/(σelT)) in the abovementioned regime of strong magnetic field and finite chemical potential shows linear enhancement with the temperature and has smaller magnitude than the isotropic one, thus, it describes the violation of the Wiedemann–Franz law for the hot and dense QCD matter in the presence of a strong magnetic field.

Magnetic field-dependent thermal transport in a spin-1/2 chain compound

2008 ◽  
Vol 403 (5-9) ◽  
pp. 1445-1446 ◽  
Author(s):  
A.V. Sologubenko ◽  
K. Berggold ◽  
T. Lorenz ◽  
A. Rosch ◽  
E. Shimshoni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Transport ◽  
Field Dependent ◽  
Chain Compound

Thermal conductivity and electrical resistivity of c-axis oriented polycrystalline (BI,Pb)2Sr2Ca2Cu3Ox in a magnetic field

1994 ◽  
Vol 235-240 ◽  
pp. 1509-1510 ◽  
Author(s):  
K. Mori ◽  
A. Tanaka ◽  
K. Nishimura ◽  
J. Sakurai ◽  
T. Sasaki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Oriented Polycrystalline
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