Research Development on Sodium-Ion Batteries

In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

The purpose of this critical review is to give a representative and comprehensive overview of the arising developments in the field of magnetic metal–organic frameworks, in particular those containing cobalt(II). We examine the diversity of magnetic exchange interactions between nearest-neighbour moment carriers, covering from dimers to oligomers and discuss their implications in infinite chains, layers and networks, having a variety of topologies. We progress to the different forms of short-range magnetic ordering, giving rise to single-molecule-magnets and single-chain-magnets, to long-range ordering of two- and three-dimensional networks (323 references).

Magnetic metal-organic frameworks.

Publisher Summary This review is concerned with the neglected class of inorganic compounds, which contain ions of the same element in two different formal states of oxidation. Although the number of references cited in our review show that many individual examples of this class have been studied, yet they have very rarely been treated as a class, and there has never before, to our knowledge, been a systematic attempt to classify their properties in terms of their electronic and molecular structures. In the past, systems containing an element in two different states of oxidation have gone by various names, the terms “mixed valence,” nonintegral valence,” “mixed oxidation,” “oscillating valency,” and “controlled valency” being used interchangeably. Actually, none of these is completely accurate or all-embracing, but in our hope to avoid the introduction of yet another definition, we have somewhat arbitrarily adopted the phrase “mixed valence” for the description of these systems. The concept of resonance among various valence bond structures is one of the cornerstones of modern organic chemistry.

Mixed Valence Chemistry-A Survey and Classification

Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics

Charge disproportionation in CaFeO3 studied with the Mössbauer effect

Preparation and characterization of stoichiometric CaFeO3

The phase diagram of the system BaO-Fe203 was determined by X-ray diffraction, melting-point measurement, and microscopic methods. Since the reduction of Fe3+ to Fe2+ was observed by chemical analysis in the samples heated at high temperature, especially in molten samples, the samples were heated at 1 atmosphere pressure of oxygen in the temperature region in which the liquid was in equilibrium; 1 atmosphere pressure of oxygen was su5cient to restrain the reduction of Fe3+. In the temperature region of solid-solid equilibrium, the dissociation was not observed even when the samples were heated in air. BaO - 6Fe2O3 formed a solid solution with BaO.Fe203. The BaO:Fe203 ratio of the solid solution was BaO.4.5Fe203 at 1350°C. and BaO. 5.0Fe20a at 800°C. The precipitation micro-structures of each primary solid solution were observed.

Phase Diagram of the System BaO‐Fe2O3

Influence of substrate temperature and film thickness on the structure of reactively evaporated In2O3 films

Multilayered films with artificial superstructures were synthesized by alternate deposition of Fe and V in ultrahigh vacuum. X-ray diffraction confirmed the establishment of artificial periodicities with very short wavelengths, e.g. Fe(4 A)-V(8 A) of the minimum case, and bcc [110] texture. Magnetic properties as a function of Fe layer thickness were studied from Mossbauer and SQUID measurements. Local magnetization at the Fe interface layer contacting with V is discussed from Mossbauer results on surface-selectively enriched samples and also from polarized neutron diffraction experiments.

Toshio Takada

Papers

Charge disproportionation in CaFeO3 studied with the Mössbauer effect

Preparation and characterization of stoichiometric CaFeO3

Phase Diagram of the System BaO‐Fe2O3

Influence of substrate temperature and film thickness on the structure of reactively evaporated In2O3 films

Magnetic Properties of Fe-V Multilayered Films with Artificial Superstructures