0000000000194684
AUTHOR
A. V. Ragulya
showing 4 related works from this author
Synthesis of Nanoferroics
2013
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 tem…
The Peculiar Physical Properties of Nanosized Ferroics (Nanoferroics)
2013
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 re…
True Nanoferroics with the Properties Absent in Corresponding Bulk Samples
2013
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 nanosa…
Theoretical Description of Primary Nanoferroics. Comparison of the Theory with Experiment
2013
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…