Functional Metal Oxides

Satishchandra Ogale is a Chief Scientist and Coordinator of the Centre of Excellence in Solar Energy at the National Chemistry Laboratory (CSIR-NCL) in Pune (India), and a Professor of Physical Sciences at the AcSIR, CSIR, New Delhi. After obtaining his academic degrees from the University of Poona, he spent nine years as Senior Researcher at the University of Maryland, College Park, (USA). Dr. Ogale has authored more than 370 research publications and one book. His current interest is in the fi eld of nanostructured metal oxides for energy applications. Venky Venkatesan had a 17 year stint at Bell Labs and Bellcore before moving to the University of Maryland. While at Bell he was the founding Director of the Surface Modification and Interface Dynamics Laboratory at Rutgers University. After the canonical 17 years he moved to the National University of Singapore to establish a Nano Institute there, NUSNNI-NanoCore. He is known for the invention of the PLD process and has over 500 publications in the area of oxide thin films, heterostructures and interfaces. He is among the top 100 most cited Physicists, Fellow of the American Physical Society, winner of the Bellcore Award of Excellence, and the George E Pake Prize of the APS in 2012. He is the founder and Chairman of Neocera, a company specializing in pulsed energy deposition systems and magnetic imaging systems for semiconductor device analysis. Mark Blamire is Professor of Device Materials and Head of the Materials Science Department at the University of Cambridge (UK). He has studied and worked at the University of Cambridge since he was an undergraduate. Prof. Blamire has authored more than 400 research publications and is a Fellow of the Institute of Physics. His research is based on the study of novel materials or new materials combinations for potential device applications. These materials include metals, oxides, nitrides with properties such as superconductivity, magnetism and ferroelectricity.

PREFACE

PART I: Magnetic Oxides

INTRODUCTION TO MAGNETIC OXIDES
Oxide Structures and Crystal Chemistry
Oxide Growth
Magnetic Properties of 3d and 4f Ions
Magnetic Interactions in Oxides
Concentrated Magnetic Oxides
Dilute Magnetic Oxides
Conclusions

MAGNETIC/MULTIFUNCTIONAL DOUBLE PEROVSKITE OXIDE THIN FILMS
Introduction
Thin-Film Deposition
Structure and Morphology
Electronic Structure
Physical Properties
Applications of Multifunctional Oxides
Future Directions

PART II: Dopants, Defects and Ferromagnetism in Metal Oxides

MAGNETIC OXIDE SEMICONDUCTORS: ON THE HIGH-TEMPERATURE FERROMAGNETISM IN TIO2- AND ZNO-BASED COMPOUNDS
Introduction
Properties of (Ti,Co)O2
Properties of Transition-Metal-Doped ZnO
Discussion
Summary and Outlooks

EFFECT OF TA ALLOYING ON THE OPTICAL, ELECTRONIC, AND MAGNETIC PROPERTIES OF TIO2 THIN FILMS
Introduction
Ta Substitution in TiO2: Doping or Alloying?
Diluted Magnetic Semiconductors (DMS)
Defect-Mediated Ferromagnetism
Magnetic Impurity Analysis in Ti1-xTaxO2 System
Defect-Induced Ferromagnetism in Ti1-xTaxO2 Film
First-Principles Spin-Polarized GGA + U Calculations
Mechanism of Defect-Mediated FM
Optimization of Ferromagnetism
Outlook for Defect-Mediated Properties of Ti1-xTaxO2

DEFECT-INDUCED OPTICAL AND MAGNETIC PROPERTIES OF COLLOIDAL TRANSPARENT CONDUCTING OXIDE NANOCRYSTALS
Introduction
Colloidal Transition-Metal-Doped Transparent Conducting Oxide Nanocrystals
Native Defects in Colloidal Transparent Conducting Oxide Nanocrystals
Summary and Outlook

PART III: Ferroelectrics

STRUCTURE - PROPERTY CORRELATIONS IN RARE-EARTH-SUBSTITUTED BIFEO3 EPITAXIAL THIN FILMS AT THE MORPHOTROPIC PHASE BOUNDARY
Introduction
Combinatorial Discovery of a MPB in Sm-substituted BiFeO3 (Sm-BFO)
Structural Evolution across the MPB in Sm-BFO
Universal Behavior in RE-Substituted BFO
Structural Fingerprint of MPB in RE-Substituted BFO
Chemical-Substitution-Induced Polarization Rotation in BFO
Concluding Remarks and Future Perspectives

ANTIFERROELECTRICITY IN OXIDES: A REEXAMINATION
Introduction
Definition and Characteristic Properties
Microscopic Origins of Macroscopic Behavior
Antiferroelectric Materials: Structure and Properties
Relation to Alternative Ferroelectric Phases
Antiferroelectricity in Thin Films
Properties for Applications
Prospects

PART IV: Multiferroics

PROBING NANOSCALE ELECTRONIC CONDUCTION IN COMPLEX OXIDES
Scanning-Probe-Based Transport Measurements
Domain Wall Conductivity
Photovoltaic Effects at Domain Walls
Local Characterization of Doped Oxides and Defects
Local Electronic Probing of Oxide Interfaces
Nanoscale Electronic Properties of CMR Manganites
Future Directions

MULTIFERROICS WITH MAGNETOELECTRIC COUPLING
Introduction: Ferroic Materials
Principles of Symmetry Analysis
Magnetoelectric Couplings and a Landau-Like Theory
Chemical Considerations
Classification of Multiferroics
Multiferroic Materials and Mechanisms
Microscopic Mechanisms of Magnetic Ferroelectricity: Type II Multiferroics
Domains and Metal - Insulator Transition

PART V: Interfaces and Magnetism

DEVICE ASPECTS OF THE SRTIO3 - LAALO3 INTERFACE; BASIC PROPERTIES, MOBILITY, NANOSTRUCTURING, AND POTENTIAL APPLICATIONS
Introduction
The LaAlO3/SrTiO3 Interface: Key Characteristics and Understanding
Charge-Carrier Mobility
Micro/Nanostructuring
Electric Field Gating
Applications

X-RAY SPECTROSCOPIC STUDIES OF CONDUCTING INTERFACES BETWEEN TWO INSULATING OXIDES
Introduction
Photoemission Measurements of Interfaces
Interfaces between a Mott Insulator and a Band Insulator: LaAlO3/LaVO3 and LaTiO3/SrTiO3
Interfaces between Two Band Insulators: LaAlO3/SrTiO3
Summary

INTERFACIAL COUPLING BETWEEN OXIDE SUPERCONDUCTORS AND FERROMAGNETS
Introduction
Experimental Results
Materials Considerations
Conclusions

PART VI: Devices and Applications

METAL-OXIDE NANOPARTICLES FOR DYE-SENSITIZED SOLAR CELLS
TiO2: Polymorphism, Optoelectronic Properties, and Bandgap Engineering
Principle and Basis of Dye-Sensitized Solar Cell (DSC) Technology
Progress in TiO2 Engineering for Improved Charge-Collection Efficiency and Light Confinement
Development of Molecular Sensitizers Suited to TiO2 Optoelectronic Properties
Development of Redox Mediators
Conclusions
HYBRID SOLAR CELLS FROM ORDERED NANOSTRUCTURES
Introduction
Working Mechanisms of Hybrid Solar Cells
Nanostructures for Hybrid Solar Cells
Metal Oxide Modifications
Conclusion and Outlook

ELECTRIC FIELD EFFECTS IN FUNCTIONAL METAL OXIDES
Introduction
Developments of Gate Dielectrics: from High-k Oxides to Ionic Electrolytes
Electric-Field-Induced Modulation of Ferromagnetism
Electrostatic Modulation of Superconductivity
Transparent Amorphous Metal-Oxide Field-Effect Transistors
Solution-Processable Transparent Amorphous Metal Oxides for Thin-Film Transistors
Challenges and Opportunities

RESISTIVE SWITCHINGS IN TRANSITION-METAL OXIDES
Introduction
Classification of Current - Voltage Hystereses
Bipolar Continuous Switching
Toward Device Applications and Summary

INDEX