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Synthesis and Characterization of Fe...

Jia, Yue.

Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices.
Author:	Jia, Yue.
Published:	Ann Arbor : ProQuest Dissertations & Theses, 2017
Description:	129 p.
Notes:	Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
Notes:	Adviser: Yayoi Takamura.
Contained By:	Dissertation Abstracts International79-01B(E).
Subject:	Materials science.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10262276
ISBN:	9780355149258

Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices.
Jia, Yue.

Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices. - Ann Arbor : ProQuest Dissertations & Theses, 2017 - 129 p.

Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.

Thesis (Ph.D.)--University of California, Davis, 2017.

Perovskite oxides span a diverse range of functional properties such as ferromagnetism, superconductivity, and ferroelectricity, which makes them promising candidate materials for applications such as sensors, energy conversion and data storage devices. With recent advances in thin film deposition techniques, the precise manipulation of atomic layers on the unit cell level make it possible to synthesize epitaxial thin film heterostructures consisting of layers with different properties. The structural compatibility of perovskite oxides allows them to be epitaxially grown in complex heterostructures such as superlattices with a large density of interfaces where the interplay between spin, charge, orbital, and lattice degrees of freedom gives rise to new behaviors. The ferromagnetic (FM)/antiferromagnetic (AF) interface is particularly interesting due to exchange coupling which is not only of interest for fundamental research but also is of great significance for industrial applications. Unlike metallic systems that have been studied for decades with wide ranges of applications in devices such as hard disk drives, thin films of complex metal oxides is a relatively new field. Perovskite oxides show much more diverse functional properties than metals and open new pathways for tailoring propertiestowards specific device applications.

ISBN: 9780355149258Subjects--Topical Terms:

221779
Materials science.

Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices.
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245 1 0 $a Synthesis and Characterization of Ferromagnetic/Antiferromagnetic Perovskite Oxide Superlattices.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2017
300 $a 129 p.
500 $a Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
500 $a Adviser: Yayoi Takamura.
502 $a Thesis (Ph.D.)--University of California, Davis, 2017.
520 $a Perovskite oxides span a diverse range of functional properties such as ferromagnetism, superconductivity, and ferroelectricity, which makes them promising candidate materials for applications such as sensors, energy conversion and data storage devices. With recent advances in thin film deposition techniques, the precise manipulation of atomic layers on the unit cell level make it possible to synthesize epitaxial thin film heterostructures consisting of layers with different properties. The structural compatibility of perovskite oxides allows them to be epitaxially grown in complex heterostructures such as superlattices with a large density of interfaces where the interplay between spin, charge, orbital, and lattice degrees of freedom gives rise to new behaviors. The ferromagnetic (FM)/antiferromagnetic (AF) interface is particularly interesting due to exchange coupling which is not only of interest for fundamental research but also is of great significance for industrial applications. Unlike metallic systems that have been studied for decades with wide ranges of applications in devices such as hard disk drives, thin films of complex metal oxides is a relatively new field. Perovskite oxides show much more diverse functional properties than metals and open new pathways for tailoring propertiestowards specific device applications.
520 $a Epitaxial La0.7Sr0.3MnO3 (LSMO)/La 0.7Sr0.3FeO3 (LSFO) superlattices serve as model systems to explore the magnetic structure and exchange coupling at perovskite oxide interfaces. Earlier work suggested that (001)-oriented LSMO/LSFO superlattices with compensated AF spins at the interface display spin-flop coupling characterized by perpendicular alignment between the AF spin axes and the FM moments at a sublayer thickness of 6 unit cells (u.c.). Changing the crystallographic orientation of the interface from (001) to (111) introduces changes to factors such as the charge density of each stacking layer, the magnetic iiistructure of the AF layer at the interface, the symmetry of the lattice, and the orbital degeneracy. Therefore, different properties and exchange coupling mechanisms are expected.
520 $a (111)-oriented LSMO/LSFO superlattices with sublayer thicknesses ranging from 3 to 60 u.c. were synthesized and characterized. Detailed analysis of their structural, electronic, and magnetic properties were performed using synchrotron radiation based resonant x-ray reflectivity, soft x-ray magnetic spectroscopy, and photoemission electron microscopy to explore the effect of sublayer thickness on the magnetic structure and exchange coupling at (111)-oriented perovskite oxide interfaces. Interfacial effects and ultrathin superlattice sublayers can stabilize orientations of the LSFO AF spin axis which differ from that of LSFO films and LSMO/LSFO bilayers. In the ultrathin limit (3 to 6 u.c.), it was found that the AF properties of the LSFO sublayers are preserved with an out-of-plane canting of the AF spin axis, while the FM properties of the LSMO sublayers are significantly depressed. For thicker LSFO layers (> 9 u.c.), the out-of-plane canting of the AF spin axis is only present in superlattices with thick LSMO sublayers. As a result, exchange coupling in the form of spin-flop coupling exists only in superlattices which display both robust ferromagnetism and out-of-plane canting of the AF spin axis. A portion of the AF moments can be reoriented by a moderate external magnetic field through spin-flop coupling with the FM LSMO sublayers that have low magnetocrystalline anisotropy in the (111) plane. The AF order in the spin-flop coupled superlattices was studied using angle-dependent x-ray magnetic linear dichroism. The AF order can be categorized into two types: majority of the AF moments cant out-of-the-plane of the film along the or directions depending on the LSFO layer thickness, while a minority portion lies within the (111) plane in different AF domains. The energy difference between domains with their spin axes along the in-plane or out-of-plane directions is small, and the magnetic order of AF thin films is far ivmore complex than in bulk LSFO. The complex AF structure in these (111)-oriented LSMO/LSFO superlattices illustrates that complex metal oxide heterostructures can serve as fertile ground for discovery of new magnetic phases, which have potential applications in next generation information technology devices.
590 $a School code: 0029.
650 4 $a Materials science. $3 221779
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710 2 $a University of California, Davis. $b Materials Science and Engineering. $3 730230
773 0 $t Dissertation Abstracts International $g 79-01B(E).
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