scholarly journals Calculation of Electrical Conductivity and Giant Magnetoresistance within the Free Electron Model

1995 ◽  
Vol 384 ◽  
Author(s):  
X.-G. Zhang ◽  
W. H. Butler
Keyword(s):  
Electrical Conductivity ◽  
Free Electron ◽  
Giant Magnetoresistance ◽  
Magnetic Layer ◽  
Random Point ◽  
Free Electrons ◽  
Electron Model ◽  
Multilayer Systems ◽  
Free Electron Model ◽  
Experimental Values

ABSTRACTWe use the model of free electrons with random point scatterers (FERPS) to calculate the electrical conductivity and giant magnetoresistance (GMR) for FeCr multilayer systems and compare our results with the experimental values. Our analysis suggests that the primary cause of the GMR in FeCr systems is regions of interdiffusion near the interfaces. We find that in the samples analyzed, these regions of interdiffusion occupy about 8.5Å of the magnetic layer near each interface.

scholarly journals Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors

2017 ◽  
Vol 114 (45) ◽  
pp. 11873-11877 ◽  
Author(s):  
Mohamed Zaghoo ◽  
Isaac F. Silvera
Keyword(s):  
Electrical Conductivity ◽  
Model Fitting ◽  
Theoretical Models ◽  
Metallic Hydrogen ◽  
Dynamo Action ◽  
Electron Model ◽  
Experimental Constraint ◽  
Free Electron Model ◽  
Experimental Values ◽  
Spectrally Resolved

Liquid metallic hydrogen (LMH) is the most abundant form of condensed matter in our solar planetary structure. The electronic and thermal transport properties of this metallic fluid are of fundamental interest to understanding hydrogen’s mechanism of conduction, atomic or pairing structure, as well as the key input for the magnetic dynamo action and thermal models of gas giants. Here, we report spectrally resolved measurements of the optical reflectance of LMH in the pressure region of 1.4–1.7 Mbar. We analyze the data, as well as previously reported measurements, using the free-electron model. Fitting the energy dependence of the reflectance data yields a dissociation fraction of 65 ± 15%, supporting theoretical models that LMH is an atomic metallic liquid. We determine the optical conductivity of LMH and find metallic hydrogen’s static electrical conductivity to be 11,000–15,000 S/cm, substantially higher than the only earlier reported experimental values. The higher electrical conductivity implies that the Jovian and Saturnian dynamo are likely to operate out to shallower depths than previously assumed, while the inferred thermal conductivity should provide a crucial experimental constraint to heat transport models.

scholarly journals FREE ELECTRON MODEL STUDY ON INTERLAYER EXCHANGE COUPLING IN MAGNETIC MULTILAYERS

1996 ◽  
Vol 45 (5) ◽  
pp. 869
Author(s):  
YANG GUO-LIN ◽  
LI BO-ZANG ◽  
LI LIE-MING ◽  
SUN GANG ◽  
WU JIAN-HUA ◽  
...  
Keyword(s):  
Free Electron ◽  
Exchange Coupling ◽  
Magnetic Multilayers ◽  
Interlayer Exchange Coupling ◽  
Electron Model ◽  
Model Study ◽  
Free Electron Model ◽  
Interlayer Exchange

scholarly journals On some electron properties of tellurium and Wilson's mechanism of semi-conductivity

1935 ◽  
Vol 148 (865) ◽  
pp. 648-664 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Free Electron ◽  
Previous Investigation ◽  
Room Temperature ◽  
Specific Resistance ◽  
Mean Free Path ◽  
Free Electrons ◽  
Conduction Electrons ◽  
Classical Statistics ◽  
Limiting Case

In a previous investigation it was found that the unusually high value for the Wiedemann-Franz ratio of tellurium could be explained as being only a formal anomally. The amount of heat transferred by the bound atoms is the same in tellurium as in conducting metals; but, in tellurium, in contrast to good conductors, it is responsible for almost the entire heat conductivity because the heat transferred by the free electrons is especially small. This indicates that tellurium differs from true metals in that the density of free electrons is very small. Classical statistics is therefore applicable and the electrical conductivity is given by x = 4/3 e 2 ln (2 πmk T) -5/9 , (1) where n is the density of free (conduction) electrons and l is their mean free path. Taking the specific resistance of tellurium at room temperature as 0.3 ohm-cm and l as 5.2 X 10 -6 cm (Sommerfeld's value for silver, found by applying Fermi-Dirac statistics), n is 2.9 X 10 16 , or about one free electron per million tellurium atoms in contrast to good conductors in which there is approximately one free electron per atom. Even in the limiting case with l = 3.2 X 10 -3 cm (the distance between the tellurium atoms), n is 4.7 X 10 18 which is about one free electron for every 6000 tellurium atoms.

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