Author: Lindsey Erin NoskinPublisher:
ISBN:
Category :
Languages : en
Pages : 32
Book Description
Study of the Metal-insulator Transition in LaCoO3-x Epitaxial Films
Author: Lindsey Erin NoskinMetal-insulator Transition in Epitaxial V2O3 Thin Films
Author: Bamidele S. AllimiConfinement-driven Metal-insulator Transition and Polarity-controlled Conductivity of Epitaxial LaNiO3/LaAlO3 (111) Superlattices
Author: Haoming WeiEpitaxial Growth of La-Ca-Mn-O Thin Films with Ultra-sharp Metal-insulator Transition
Author: Chi Hung LeungPublisher:
ISBN:
Category : Magnetoresistance
Languages : en
Pages :
Book Description
Epitaxial Growth of Complex Metal Oxides
Author: Gertjan KosterPublisher: Elsevier
ISBN: 1782422552
Category : Technology & Engineering
Languages : en
Pages : 505
Book Description
The atomic arrangement and subsequent properties of a material are determined by the type and conditions of growth leading to epitaxy, making control of these conditions key to the fabrication of higher quality materials. Epitaxial Growth of Complex Metal Oxides reviews the techniques involved in such processes and highlights recent developments in fabrication quality which are facilitating advances in applications for electronic, magnetic and optical purposes. Part One reviews the key techniques involved in the epitaxial growth of complex metal oxides, including growth studies using reflection high-energy electron diffraction, pulsed laser deposition, hybrid molecular beam epitaxy, sputtering processes and chemical solution deposition techniques for the growth of oxide thin films. Part Two goes on to explore the effects of strain and stoichiometry on crystal structure and related properties, in thin film oxides. Finally, the book concludes by discussing selected examples of important applications of complex metal oxide thin films in Part Three. Provides valuable information on the improvements in epitaxial growth processes that have resulted in higher quality films of complex metal oxides and further advances in applications for electronic and optical purposes Examines the techniques used in epitaxial thin film growth Describes the epitaxial growth and functional properties of complex metal oxides and explores the effects of strain and defects
Preparation and Properties of Epitaxial Thin Films of La1-Xbaxmn03 on Various Substrated
Author: Ngai-Shek SoongPublisher: Open Dissertation Press
ISBN: 9781361192412
Category :
Languages : en
Pages :
Book Description
This dissertation, "Preparation and Properties of Epitaxial Thin Films of La1-xBaxMn03 on Various Substrated" by Ngai-shek, Soong, 宋毅碩, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled PREPARATION AND PROPERTIES OF EPITAXIAL THIN FILMS OF La Ba MnO ON VARIOUS SUBSTRATES 1-x x 3 submitted by Ngai-Shek SOONG for the degree of Master of Philosophy at The University of Hong Kong in December 2002 Epitaxial thin films of La Ba MnO (LBMO) were on deposited SrTiO 0.8 0.2 3 3 (100) (STO), LaAlO (100) (LAO), MgO (100) and Y O - ZrO (100) (YSZ) 3 2 3 2 substrates by using an off-axis magnetron sputtering. The properties of fabricated LBMO thin films were studied by using X-ray diffraction, dc four-probe measurements, surface profiler and atomic force microscopy. For LBMO thin films grown on STO, X-ray diffraction patterns showed that the films were highly c-axis oriented and fully epitaxial. The obtained values of full width at half maximum (FWHM) of the (002) rocking curves were small, indicating good crystallinity of the films. The temperature of insulator-metal transition, T, decreased as the thickness of the thin film increased. This was different from other systems with similar perovskite structure such as La Ca MnO and La Sr MnO . The electrical 1-x x 3 1-x x 3 resistivity of LBMO/STO thin film for temperature T2 4.5 expression of ρ(T) =ρ +ρ T +ρ T (Eq.1). The values of ρ ρ ρ all increased 0 2 4.5 0, 2, 4.5 with increasing thickness d, except d=350A, implying a phase transition may have occured. The anomalous electrical behavior of LBMO/STO system could not be explained by considering only the decreasing of transfer integral on in-plane e electrons. The orbital degree of freedom played a crucial role in determining the electrical properties of tensile-stressed LBMO thin films due to the relatively large ratio of c/a. For LBMO/LAO thin films, X-ray diffraction patterns and small FWHM values implied good crystallinity of the thin films. The decreasing value of out-of- plane lattice parameters with increasing thickness suggested the existence of compressive strain within the LBMO/LAO system. The temperature dependence of resistivity measurement showed that T decreases as the thickness of thin film increased. This is consistent with the double-exchange theory, which states that compressive strain enhances T . The temperature dependence of resistivity of LBMO/LAO thin films were also fitted well to expression (Eq.1), The values of ρ 0, ρ ρ all increased with increased thickness. 2, 4.5 La Ba MnO was also deposited on YSZ or MgO substrates respectively, 0.8 0.2 3 which having larger lattice mismatch. Peaks other than (00l) orientation were observed in X-ray measurements indicating the thin films were c-axis oriented but not highly epitaxial. A fairly large value of the FWHM of the (002) diffraction peak suggested that the films were highly crystalline. Insulator-metal (I-M) transition were not observed in LBMO/MgO films and only appear in LBMO/YSZ films with d>1200A. These were mainly due to that large lattice mismatches between LBMO and YSZ or MgO substrates which generate a large number of grains and grain boundaries in the thin films, which in turn decrease the electron transfer integral. DOI: 10.5353/th_b2663683 Subjects: Thin films Epitaxy
Strain Tuning of Electronic Structure in Bi4Ti3O12-LaCoO3 Epitaxial Thin Films
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this study, we investigated the crystal and electronic structures of ferroelectric Bi4Ti3O12 single-crystalline thin films site-specifically substituted with LaCoO3 (LCO). The epitaxial films were grown by pulsed laser epitaxy on NdGaO3 and SrTiO3 substrates to vary the degree of strain. With increasing the LCO substitution, we observed a systematic increase in the c-axis lattice constant of the Aurivillius phase related with the modification of pseudo-orthorhombic unit cells. These compositional and structural changes resulted in a systematic decrease in the band gap, i.e., the optical transition energy between the oxygen 2p and transition-metal 3d states, based on a spectroscopic ellipsometry study. In particular, the Co 3d state seems to largely overlap with the Ti t2g state, decreasing the band gap. Interestingly, the applied tensile strain facilitates the band-gap narrowing, demonstrating that epitaxial strain is a useful tool to tune the electronic structure of ferroelectric transition-metal oxides.
Progress Report on Epitaxial Films of Metals and Semiconductors
Author: Virginia Institute for Scientific ResearchPublisher:
ISBN:
Category :
Languages : en
Pages : 306
Book Description
Epitaxial Growth and RIXS Study of LaCoO3 Thin Films
Author: Thickness-dependent Metal-insulator Transition in Epitaxial SrRuO3 Ultrathin Films
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Transport characteristics of ultrathin SrRuO3 films, deposited epitaxially on TiO2-terminated SrTiO3 (001) single-crystal substrates, were studied as a function of film thickness. Evolution from a metallic to an insulating behavior is observed as the film thickness decreases from 20 to 4 unit cells. In films thicker than 4 unit cells, the transport behavior obeys the Drude low temperature conductivity with quantum corrections, which can be attributed to weak localization. Fitting the data with 2-dimensional localization model indicates that electron-phonon collisions are the main inelastic relaxation mechanism. In the film of 4 unit cells in thickness, the transport behavior follows variable range hopping model, indicating a strongly localized state. As a result, magnetoresistance measurements reveal a likely magnetic anisotropy with the magnetic easy axis along the out-of-plane direction.