Studies of (La,Ca)MnO[sigma] thin film with giant magnetoresistance prepared by facing target sputtering technique.

by Xianting Zeng.Publication date from spine.Thesis (Ph.D.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 165-173).ABSTRACT --- p.iiiACKNOWLEDGEMENT --- p.vTABLE OF CONTENTS --- p.viiLIST OF FIGURES --- p.xLIST OF TABLES --- p.xivChapter I. --- Introduction --- p.1Chapter 1.1 --- Previous research on magnetoresistance --- p.1Chapter 1.2 --- Preparation methods --- p.12Chapter 1.3 --- Application prospects and existing problems of GMR materials --- p.15Chapter 1.4 --- Main contents in this thesis --- p.17Chapter II. --- The facing-target sputtering technique --- p.20Chapter 2.1 --- Brief description of FTS method --- p.20Chapter 2.2 --- Considerations and studies about the deposition conditions of La-Ca-Mn-O thin films --- p.26Chapter 2.2.1 --- Substrate materials --- p.26Chapter 2.2.1.1 --- Mismatch of lattice constant --- p.26Chapter 2.2.1.2 --- Thermal expansion coefficient --- p.31Chapter 2.2.1.3 --- Cleaning and surface treatment --- p.33Chapter 2.2.2 --- Substrate temperature --- p.35Chapter 2.2.3 --- Discharge pressure and sputtering power --- p.36Chapter 2.2.4 --- Oxygen content and critical thickness --- p.36Chapter 2.3 --- Fabrication and characteristics of La-Ca-Mn-O target materials --- p.42Chapter 3.2.1 --- Fabrication process --- p.42Chapter 2.3.2 --- Characterizations --- p.46Chapter 2.3.2.1 --- Structural parameters --- p.46Chapter 2.3.2.2 --- Electrical and magnetic properties --- p.51Chapter III. --- Growth of La-Ca-Mn-O thin films with c-axis orientation --- p.53Chapter 3.1 --- Thin film deposition --- p.53Chapter 3.2 --- Characterization methods --- p.53Chapter 3.2.1 --- XRD --- p.54Chapter 3.2.2 --- SEM/EDX --- p.54Chapter 3.2.3 --- VSM --- p.57Chapter 3.3 --- Results and discussions --- p.58Chapter 3.3.1 --- Structures of the films grown on (100) MgO --- p.58Chapter 3.3.2 --- Resistance and magnetoresistance --- p.62Chapter 3.3.3 --- Annealing effect --- p.69Chapter 3.4.3.4 --- Magnetization --- p.71Chapter 3.4 --- Conclusion --- p.75Chapter IV. --- Epitaxial growth of single crystal LCMO thin films with a-axis orientation --- p.77Chapter 4.1 --- Motivation and thin film deposition --- p.77Chapter 4.2 --- Characterizations --- p.79Chapter 4.2.1 --- DCD/GID --- p.79Chapter 4.2.2 --- Laue diffractometry --- p.84Chapter 4.3 --- Results and discussions --- p.85Chapter 4.4 --- Conclusion --- p.91Chapter V. --- Crystal growth mechanisms in the deposition of LCMO thin films --- p.93Chapter 5.1 --- Introduction --- p.93Chapter 5.2 --- AFM/STM --- p.96Chapter 5.3 --- Step-flow growth --- p.100Chapter 5.4 --- Roughening growth --- p.107Chapter 5.5 --- 3-D growth --- p.111Chapter 5.6 --- Conclusion --- p.119Chapter VI. --- Anisotropy properties of epitaxial LCMO thin films and colossal low field magnetoresistance --- p.122Chapter 6.1 --- Introduction --- p.122Chapter 6.2 --- Experiments --- p.124Chapter 6.3 --- Results and discussions --- p.125Chapter 6.3.1 --- Morphology --- p.125Chapter 6.3.2 --- Transport properties --- p.125Chapter 6.4 --- Conclusion --- p.134Chapter VII. --- Optical response of epitaxial LCMO thin films --- p.135Chapter 7.1 --- Introduction --- p.135Chapter 7.2 --- Experimental procedures --- p.138Chapter 7.2.1 --- Sample preparation --- p.138Chapter 7.2.2 --- Measurements of the optical spectra --- p.140Chapter 7.2.3 --- Measurements of the optical response --- p.140Chapter 7.3 --- Experimental results and discussions --- p.142Chapter 7.3.1 --- Optical spectra --- p.142Chapter 7.3.2 --- Optical response characteristics --- p.145Chapter 7.3.3 --- 1/f noise in LCMO materials --- p.148Chapter 7.4 --- Potential applications --- p.154Chapter 7.5 --- Conclusion --- p.156Chapter VIII. --- Conclusion and further studies --- p.158Chapter 8.1 --- Conclusion --- p.158Chapter 8.2 --- Further studies --- p.161References --- p.16