Ebook: Nanoferroics

Monograph. — Springer 2013. — 378 p.The Chapter covers the theoretical and experimental approaches to the investigations of the physical properties, which are inherent in ferroics of nanosize and absent in corresponding bulk materials. Namely, the strong surface influence along with other effects of geometrical confinement generates number of physical effects, which do not occur in bulk ferroics samples. One example of such phenomena is room-temperature ferromagnetism in nanoparticles and thin films of undoped CeO2, HfO2, SnO2, Al2O3 and other nonmagnetic (in bulk samples) oxides. Theo other striking example is appearance of so-called spontaneous flexoeffects (i.e. flexoelectric, flexomagnetic, flexoelastic) in ferroic nanosamples due to strong gradient terms generated by the effects of geometrical confinement. We predict strong altering of phase transition temperature, magnetic and/or dielectric susceptibilities, piezomoduli and other physical properties of nanoferroics by the above spontaneous flexoeffects. Latter permits to describe many previously unclear experimental resultsContentsFerroics
The Definition and Classification of Ferroics
General Features of the Primary Ferroics
Field Dependence of Order Parameter
Hysteresis Loops
Thermodynamic Theory of Primary Ferroics
Secondary and Higher-Order Ferroics (Multiferroics)
General Information
Magnetoelectric Effect in Ferromagnetic Ferroelectrics
Short-Range Order Clusters in Primary Ferroic Glasses
Superparamagnets, Superparaelectrics,
Superparaelastics and Relaxors
Spin, Dipole and Quadrupole Glasses
(Orientational Glasses)
Superparaelectricity and Superparamagnetism
Relaxor Ferroelectrics
References
The Peculiar Physical Properties of Nanosized Ferroics (Nanoferroics)
Physical Factors Which Determine the Nanomaterial Properties
Experimental Investigation of Size Effects in Nanoferroics
Ferroelectric Nanomaterials
Ferromagnetic Materials
Ferroelastic Nanomaterials
References
Theoretical Description of Primary Nanoferroics. Comparison of the Theory with Experiment
Contribution of Surface Tension to Nanoferroics Properties
Ferroelectric Nanomaterials
Elastic Interactions for the Films and Nanoparticles of Different Shapes
Calculations of Physical Properties of Nanoferroelectrics by Euler-Lagrange
Equation Solution
The Influence of Built-in Electric Field on the Properties of Ferroelectric Thin Films
Thickness Induced Ferroelectricity in Antiferroelectric Thin Films
Relaxor Ferroelectric Thin Films
Specific Heat and Dielectric Permittivity in Nanogranular Ferroelectric Ceramics. The influence of Nanoparticles Size Distribution
The Peculiarities of Electron Paramagnetic and Nuclear Magnetic Resonance Spectra in Nanoferroics
Ferromagnetic Nanomaterials
Superparamagnetism of Ferromagnetic Nanoparticles
The Influence of Intergranular Interaction on the Properties of Ferromagnetic
Nanomaterials. Superferromagnetic and Superspinglass States
Nanoferroelastics
The Peculiarities of Oxygen Ionic Conductivity in Nanogranular Ceramics
References
True Nanoferroics with the Properties Absent in Corresponding Bulk Samples
Introduction
Experimental Investigation of the Properties Absent in Bulk Samples
Room-Temperature Ferromagnetism in Nanomaterials of Non-magnetic (in Bulk Samples) Oxides
New Multiferroics on the Base of Quantum
Paraelectric EuTiO₃ Thin Films
Theory. Comparison of the Theory with Experiment
Introduction
Model Assumptions
Energy Levels of the Defect with Two Electrons
(Holes) Localized Under the Surface
Pair Interaction Between Magnetic Defects
Possible Mechanisms of Defects-Induced
Ferromagnetic Order Near the Surface
Anion Vacancy-Driven Magnetism in Incipient
Ferroelectrics SrTiO₃ and KTaO₃
The Symmetry Analysis of Piezomagnetic,
Piezoelectric and Linear Magnetoelectric Effects in Nanosystems
Spontaneous Flexoeffects in Nanoferroics
Linear Magnetoelectric Coupling and Ferroelectricity Induced by Flexomagnetic
Effect in Ferroics
Superparaelectric Phase in the Ensemble of Non-interacting Ferroelectric Nanoparticles
Ferroelectric Ferromagnet Multiferroic on the Basis of EuTiO₃ Nanowires
References
Synthesis of Nanoferroics
Classification of Synthesis of Nanoferroics
Synthesis of the Ferroic Nanopowders
Chemical Synthesis of Particular Nanoferroics
Milling and Mechanochemical Synthesis
Hydrothermal Synthesis
Co-precipitation and Sol-gel Method
Synthesis in Emulsions
Sonochemical Synthesis
Synthesis of Nanoparticles from Unstable Precursors
Getting the Magnets in the Layered and Mesoporous Nanoreactor
Synthesis of the Ferroic Nanoparticles
Accompanied by Self-Organization
Electrochemical Deposition
References
Index