Nanoferroics

Description

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