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2013 | Buch

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Nanoferroics

verfasst von: M.D. Glinchuk, A.V. Ragulya, Vladimir A. Stephanovich

Verlag: Springer Netherlands

Buchreihe : Springer Series in Materials Science

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This book covers the physical properties of nanosized ferroics, also called nanoferroics. Nanoferroics are an important class of ceramic materials that substitute conventional ceramic ferroics in modern electronic devices. They include ferroelectric, ferroelastic, magnetic and multiferroic nanostructured materials. The phase transitions and properties of these nanostructured ferroics are strongly affected by the geometric confinement originating from surfaces and interfaces. As a consequence, these materials exhibit a behavior different from the corresponding bulk crystalline, ceramic and powder ferroics. This monograph offers comprehensive coverage of size- and shape-dependent effects at the nanoscale; the specific properties that these materials have been shown to exhibit; the theoretical approaches that have been successful in describing the size-dependent effects observed experimentally; and the technological aspects of many chemical and physico-chemical nanofabrication methods relevant to making nanoferroic materials and composites. The book will be of interest to an audience of condensed matter physicists, material scientists and engineers, working on ferroic nanostructured materials, their fundamentals, fabrication and device applications.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Ferroics

Abstract

This chapter has introductory character and gives the definition and general classification of the ferroics. We classify the ferroics in terms of their order parameters and corresponding conjugated external fields (magnetic, electric, elastic). The number of the fields, which are necessary to switch a ferroic from one state to another, defines so-called primary, secondary and higher-order ferroics. For example, there are three types of primary ferroics – ferromagnets, ferroelectrics and ferroelastics, which can be switched by the application of only one kind of external field. There are six types of secondary ferroics, which can be switched by the application of two types of above fields and much more types of higher-order ferroics. The distinctive features of the nanosized ferroics (nanoferroics) have also been discussed.

M. D. Glinchuk, A. V. Ragulya, Vladimir A. Stephanovich

Chapter 2. The Peculiar Physical Properties of Nanosized Ferroics (Nanoferroics)

Abstract

This Chapter contains the experimental facts about size effects in nanoferroics. They include ferroelectric, ferroelastic, magnetic and multiferroic nanostructured materials. The main peculiar feature of nanoferroics is the geometric confinement originating from their surfaces and interfaces. This is in contrast to the ordinary bulk ferroics, where the sample surface plays a minor role. In particular, in nanoferroics, the surface generates the physical properties gradients in the normal (to the surface) direction. This fact yields strong size effects and spatial inhomogeneity of the nanoferroics properties, which should be taken into account to get their adequate physical description. We report and analyze an extensive collection of experimental results regarding nanoferroics symmetry, lattice constants, dielectric response, magnetic susceptibility, polarization and hysteresis loops, magnetization and coercive field, heat capacity, soft mode and optical properties.

M. D. Glinchuk, A. V. Ragulya, Vladimir A. Stephanovich

Chapter 3. Theoretical Description of Primary Nanoferroics. Comparison of the Theory with Experiment

Abstract

This Chapter is devoted primarily to the theoretical description of the physical properties of nanoferroics. The theoretical approach that has been successful in describing the size- and shape-dependent effects observed experimentally in nanoferroics is Landau – Ginzburg – Devonshire phenomenological theory, operating on nanoferroics symmetry and order parameters. Our analysis of this theory applicability shows that it can be safely applied down to the sample sizes of few nanometers. The main peculiarity of theoretical description of nanoferroics is that the boundary conditions and terms containing gradients of order parameters cannot be omitted and play the vital role in the description of their physical properties. The phenomenological approach can be successfully applied for the description of primary, secondary and higher orders nanoferroics. We present the comprehensive comparison of the available theoretical approaches and experimental results.

M. D. Glinchuk, A. V. Ragulya, Vladimir A. Stephanovich

Chapter 4. True Nanoferroics with the Properties Absent in Corresponding Bulk Samples

Abstract

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 results.

M. D. Glinchuk, A. V. Ragulya, Vladimir A. Stephanovich

Chapter 5. Synthesis of Nanoferroics

Abstract

The Chapter covers the technological aspects of many chemical and physico-chemical nanofabrication methods relevant to making nanoferroic materials and composites. First, the classification of relevant synthesis methods of nanoferroics has been presented. Synthesis of particular nanoferroics with different chemical bonding like metallic, oxide and non-oxide compounds is considered in details. Among the methods, the mechanochemical, sonochemical, hydrothermal, co-precipitation, emulsion, thermal decomposition of unstable precursors have been analyzed. The competition between new phase nucleation and nuclei growth has been revealed to be controlled using feedback between reaction rate and temperature. Agglomeration of nanoparticles has been studied as a phenomenon typical for nanoparticles. Surfactants are used for the synthesis of nanoparticles to reduce the interparticle interaction due to increased repulsive forces to control the particle size and their distribution in most chemical methods. We present a comparative analysis of strengths and weaknesses of all available methods for nanoferroics fabrication.

M. D. Glinchuk, A. V. Ragulya, Vladimir A. Stephanovich

Backmatter

Titel: Nanoferroics
verfasst von: M.D. Glinchuk
A.V. Ragulya
Vladimir A. Stephanovich
Verlag: Springer Netherlands
Electronic ISBN: 978-94-007-5992-3
Print ISBN: 978-94-007-5991-6
DOI: https://doi.org/10.1007/978-94-007-5992-3

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