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Observation of room temperature spin...

Chapline, Michael.

Observation of room temperature spin filtering in cobalt ferrite tunnel barriers.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Observation of room temperature spin filtering in cobalt ferrite tunnel barriers.
Author:	Chapline, Michael.
Description:	113 p.
Notes:	Adviser: Shan X. Wang.
Notes:	Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2776.
Contained By:	Dissertation Abstracts International67-05B.
Subject:	Engineering, Materials Science.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3219244
ISBN:	9780542705823

Observation of room temperature spin filtering in cobalt ferrite tunnel barriers.
Chapline, Michael.

Observation of room temperature spin filtering in cobalt ferrite tunnel barriers. - 113 p.

Adviser: Shan X. Wang.

Thesis (Ph.D.)--Stanford University, 2006.

Spintronics is a new field of electronics based upon manipulating the spin of the electron. Devices based on spintronics are attractive both because of the possibilities inherent in the quantum nature of single spins and the relatively small amount of energy required to manipulate spins. However an essential prerequisite to realizing spintronics devices are methods for generating and detecting polarized spins. One promising approach to generating polarized spins is to use a spin filter tunnel barrier that favors the transmission of one spin polarization over the other. The main object of this work was to investigate the electronic properties of CoFe2O4 and determine if it can be used as a room temperature spin filter.

ISBN: 9780542705823Subjects--Topical Terms:

226940
Engineering, Materials Science.

Observation of room temperature spin filtering in cobalt ferrite tunnel barriers.
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100 0 $a Chapline, Michael. $3 264138
245 1 0 $a Observation of room temperature spin filtering in cobalt ferrite tunnel barriers.
300 $a 113 p.
500 $a Adviser: Shan X. Wang.
500 $a Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2776.
502 $a Thesis (Ph.D.)--Stanford University, 2006.
520 # $a Spintronics is a new field of electronics based upon manipulating the spin of the electron. Devices based on spintronics are attractive both because of the possibilities inherent in the quantum nature of single spins and the relatively small amount of energy required to manipulate spins. However an essential prerequisite to realizing spintronics devices are methods for generating and detecting polarized spins. One promising approach to generating polarized spins is to use a spin filter tunnel barrier that favors the transmission of one spin polarization over the other. The main object of this work was to investigate the electronic properties of CoFe2O4 and determine if it can be used as a room temperature spin filter.
520 # $a We were able to demonstrate that CoFe2O4 can indeed be used as a room temperature spin filter by fabricating Au/CoFe2O 4/MgAl2O4/Fe3O4 junctions. The Fe3O4 electrode serves as a source of spin polarized electrons with which to probe the spin filtering properties of the CoFe 2O4 barrier. The MgAl2O4 layer was found necessary in order to magnetically decouple the CoFe2O 4 and Fe3O4 layers so that the magnetization directions of the CoFe2O4 and Fe3O4 layers could be independently varied. The evidence for spin filtering is provided by the dependence of the tunneling current versus voltage curve on the relative orientation of the magnetizations of the Fe3O4 and CoFe 2O4 layers. In order to characterize the CoFe2O 4/MgAl2O4 bilayers, we derived an analytical formula to describe the quantum mechanical tunneling current as a function of voltage bias for a bilayer tunnel barrier. This formula should be generally useful for diagnosing multilayer tunnel barriers used for resonant tunnel diodes and other novel tunnel junctions. Application of this formula to our CoFe 2O4/Fe3O4 bilayers allowed us to deduce the exchange splinting of the CoFe2O4 layer, which determines the spin filtering efficiency. Although the inferred exchange splitting was much smaller than expected, the spin polarization of electrons emitted by our devices was estimated to exceed 70%. In addition, this work demonstrates that it is possible to achieve room temperature spin filtering using magnetic tunnel barriers and this opens up the door for further development of practical spintronics devices.
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710 0 # $a Stanford University. $3 212607
773 0 # $g 67-05B. $t Dissertation Abstracts International
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790 1 0 $a Wang, Shan X., $e advisor
791 $a Ph.D.
792 $a 2006
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