國立虎尾科技大學 |

Topological Insulator/Magnetic Insulator Heterostructures : = Synthesis and Characterization.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Topological Insulator/Magnetic Insulator Heterostructures :/
Reminder of title:	Synthesis and Characterization.
Author:	Kally, James Cameron.
Description:	1 online resource (136 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 79-08(E), Section: B.
Contained By:	Dissertation Abstracts International79-08B(E).
Subject:	Materials science. -
Online resource:	click for full text (PQDT)
ISBN:	9780355776416

Topological Insulator/Magnetic Insulator Heterostructures : = Synthesis and Characterization.
Kally, James Cameron.

Topological Insulator/Magnetic Insulator Heterostructures :Synthesis and Characterization. - 1 online resource (136 pages)

Source: Dissertation Abstracts International, Volume: 79-08(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

This dissertation focuses on the applications of topological insulators for spintronics. Bismuth-chalcogenide topological insulators have large spin orbit coupling leading to surface states defined by a helical Dirac cone. These surface states have potential for spintronics due to the "spin-momentum locking" of the surface electrons, and could be efficient for the generation or detection of spin currents. To study the efficiency of topological insulators for spin to charge conversion, heterostructures of topological insulator/ferromagnetic insulators were studied by ferromagnetic resonance spin pumping. To facilitate this work different topological insulators were grown by molecular beam epitaxy on the ferromagnetic insulator yttrium iron garnet.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355776416Subjects--Topical Terms:

557839
Materials science.
Index Terms--Genre/Form:

554714
Electronic books.

Topological Insulator/Magnetic Insulator Heterostructures : = Synthesis and Characterization.
LDR:04452ntm a2200385Ki 4500 001 911005
005 20180517120326.5
006 m o u
007 cr mn||||a|a||
008 190606s2017 xx obm 000 0 eng d
020 $a 9780355776416
035 $a (MiAaPQ)AAI10799059
035 $a AAI10799059
040 $a MiAaPQ $b eng $c MiAaPQ
099 $a TUL $f hyy $c available through World Wide Web
100 1 $a Kally, James Cameron. $3 1182582
245 1 0 $a Topological Insulator/Magnetic Insulator Heterostructures : $b Synthesis and Characterization.
264 0 $c 2017
300 $a 1 online resource (136 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertation Abstracts International, Volume: 79-08(E), Section: B.
500 $a Adviser: Nitin Samarth.
502 $a Thesis (Ph.D.) $c The Pennsylvania State University $d 2017.
504 $a Includes bibliographical references
520 $a This dissertation focuses on the applications of topological insulators for spintronics. Bismuth-chalcogenide topological insulators have large spin orbit coupling leading to surface states defined by a helical Dirac cone. These surface states have potential for spintronics due to the "spin-momentum locking" of the surface electrons, and could be efficient for the generation or detection of spin currents. To study the efficiency of topological insulators for spin to charge conversion, heterostructures of topological insulator/ferromagnetic insulators were studied by ferromagnetic resonance spin pumping. To facilitate this work different topological insulators were grown by molecular beam epitaxy on the ferromagnetic insulator yttrium iron garnet.
520 $a The first challenge in this work was to grow crystalline topological insulator thin films on the yttrium iron garnet substrate. This involved utilizing multiple temperature step growth via molecular beam epitaxy. While the Bi-chalcogenide topological insulators are reasonably well latticed match to InP(111)A (a=0.415 nm, <0.2% with Bi2Se3), yttrium iron garnet has a larger cubic unit cell with 1.24 nm lattice constant. Since the Bi-chalcogenide interlayer bonds are van der Waals forces, it is possible to overcome the lattice mismatch by lowering the surface energy to promote nucleation of the topological insulator film.
520 $a Next, these topological insulator/yttrium iron garnet heterostructures were used for spin pumping studies of a pure spin current sourced from yttrium iron garnet to the topological insulator. In the topological insulator, this pure spin current is converted into a charge current. In this work, we explore the mechanism for the spin to charge conversion and determine it to be from the inverse Rashba-Eldelstein effect. The spin-charge conversion in the topological insulator is determined to be dominated by the surface states at the interface.
520 $a While the spin pumping measurements are all performed at room temperature, magnetotransport measurements were performed on the topological insulator/ferromagnetic insulator heterostructures. At temperatures below ~2K, we observed features in the magnetoresistance that are not observed in topological insulators on non-magnetic substrates. These features have a long relaxation time and the mechanism is still being explored. We hypothesize that it originates in the relaxation of paramagnetic impurities in the yttrium iron garnet substrate, resulting in a phonon bottleneck that results in a magnetocaloric effect.
520 $a Lastly, we present work on a ferromagnet metal o-MnAl with strong out of plane magnetization. This material has a strong out of plane magnetic anisotropy and could be used for spintronics applications. We demonstrated successful growth by molecular beam epitaxy on GaAs(001)B to stabilize the meta-stable tau phase. The magnetization of the film was characterized by SQUID and magneto-transport and shown to be robust with ~1T coercivity. The long term goal is to integrate this ferromagnetic layer with a topological insulator for spin-orbit torque switching devices.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Materials science. $3 557839
650 4 $a Condensed matter physics. $3 1148471
655 7 $a Electronic books. $2 local $3 554714
690 $a 0794
690 $a 0611
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a The Pennsylvania State University. $3 845556
773 0 $t Dissertation Abstracts International $g 79-08B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10799059 $z click for full text (PQDT)