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

We present a review of the basic ideas and techniques of the spectral density functional theory which are currently used in electronic structure calculations of strongly{correlated materials where the one{electron description breaks down. We illustrate the method with several examples where interactions play a dominant role: systems near metal{insulator transition, systems near volume collapse transition, and systems with local moments.

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Electronic structure calculations with dynamical mean-field theory

CRYSTALLINE MATERIALS Introduction Physical Properties Optical Properties Mechanical Properties Thermal Properties Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties GLASSES Introduction Commercial Optical Glasses Specialty Optical Glasses Fused Silica Fluoride Glasses Chalcogenide Glasses Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties Special Glasses POLYMERIC MATERIALS Optical Plastics Index of Refraction Nonlinear Optical Properties Thermal Properties Engineering Data METALS Physical Properties of Selected Metals Optical Properties Mechanical Properties Thermal Properties Mirror Substrate Materials LIQUIDS Introduction Water Physical Properties of Selected Liquids Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Commercial Optical Liquids GASES Introduction Physical Properties of Selected Gases Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Atomic Resonance Filters APPENDICES Safe Handling of Optical Materials Abbreviations, Acronyms, and Mineralogical or Common Names for Optical Materials Abbreviations for Methods of Preparing Optical Materials and Thin Films Fundamental Physical Constants Units and Conversion Factors

/pdf/handbook-of-optical-materials-3e2ukwmx2l.pdf

Handbook of Optical Materials

I. Introduction. Background. Focus of the review. Review procedure and results. The NEA-TDB data base system. Presentation of the selected data. II. Standards and Conventions. Symbols, terminology and nomenclature. Units and conversion factors. Standard and reference conditions. Fundamental physical constants. III. Selected Uranium Data. IV. Selected Auxiliary Data. V. Discussion of Data Selection. Elemental uranium. Aqua ions. Oxide, hydride and hydroxide species. VI. Discussion of Auxiliary Data Selection. Reference list. Authors list. Formula list. Discussion of selected references. Ionic strength corrections. Assigned uncertainties. The estimation of entropies.

Chemical thermodynamics of uranium

Surveys recent theories on the transition between commensurate (C) and incommensurate (I) phases, and on properties of the I phase. The devil's staircase concept for the I phase is described. Differences between theories in two and three dimensions are discussed, together with those on chaotic structures.

https://iopscience.iop.org/article/10.1088/0034-4885/45/6/001/pdf

Commensurate phases, incommensurate phases and the devil's staircase

Among cerium pnictides, the compound CeSb exhibits the most complex behavior. The magnetic structures of the numerous observed phases have been determined. The magnetic field has been applied along a fourfold axis of the rock salt structure. For all the phases the order consists of square-wave structures characterized by a propagation vector $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}=(0, 0, k)$ of value commensurate with the crystallographic cell and by a strong anisotropy confining the moments along the $k$ vector. All the structures can be generated by a periodic stacking of zero magnetized planes $P$ and ferromagnetic planes with a magnetization parallel $M\ensuremath{\uparrow}$ or antiparallel ${M}_{\ensuremath{\downarrow}}$ to the applied field. Three types of structures can be distinguished: (a) at low temperature only $M\ensuremath{\uparrow}$ and ${M}_{\ensuremath{\downarrow}}$ planes exist, the structures $k=\frac{4}{7} (++\ensuremath{-}\ensuremath{-}++\ensuremath{-})$, $k=\frac{2}{3} (++\ensuremath{-})$, and $k=0$ are successively observed when the field is increased. (b) at high temperature and low field $M\ensuremath{\uparrow}$, ${M}_{\ensuremath{\downarrow}}$, and $P$ planes coexist leading to an "antiferroparamagnetic order." (c) at high temperature and high field only $M\ensuremath{\uparrow}$ and $P$ planes exists defining a ferroparamagnetic order. The phase diagram feature can be understood by a simple thermodynamic analysis considering an entropy ${S}_{0}=k\mathrm{ln}2$ for paramagnetic planes and a moment of 2.1 ${\mathrm{\ensuremath{\mu}}}_{\mathrm{B}}$/Ce atom for magnetized planes.

Phase diagram and magnetic structures of CeSb

Neutron and magnetization studies of CeSb and CeSb1−xTex solid solutions

Magnetic properties of cerium monopnictides

The temperature dependence of the electrical resistivity and the Hall resistivity in magnetic fields up to 100 kOe is reported for US, USe, UTe, UP, UAs, and USb single crystals. The temperatures of the various first- and second-order magnetic phase transitions are derived as singularities in $\ensuremath{\rho}(T)$ and $\frac{d\ensuremath{\rho}(T)}{\mathrm{dT}}$, respectively. The magnetic part of the resistivity of the uranium monochalcogenides ($\mathrm{U}X$) is proportional to ${T}^{2}\mathrm{exp}(\frac{\ensuremath{-}\ensuremath{\Delta}}{{k}_{B}T})$, as expected for electron-magnon scattering. The value of the spin-disorder resistivity of all $\mathrm{U}X$ compounds can be interpreted with the same exchange integral. In UTe and USb, a logarithmic decrease of $\ensuremath{\rho}(T)$, known as the Kondo anomaly, is observed for $Tg{T}_{C,N}$. This behavior is discussed in the framework of existing theories and experiments on intermediate-valence and dense Kondo systems. Thus, the ferromagnetic ordering of UTe at 102 K is a new high ${T}_{C}$ for a Kondo material.

Transport properties of uranium monochalcogenide and monopnictide single crystals

Specific heat measurements have been performed on single crystals of CeSb with a magnetic field up to 70 kOe applied along a (001) direction. These results confirm that in some magnetic structures there exist non-magnetic planes in which Ce3+ ions have an entropy of about kln2.

https://iopscience.iop.org/article/10.1088/0022-3719/13/34/008/pdf

O. Vogt

Papers

Phase diagram and magnetic structures of CeSb

Neutron and magnetization studies of CeSb and CeSb1−xTex solid solutions

Magnetic properties of cerium monopnictides

Transport properties of uranium monochalcogenide and monopnictide single crystals

Specific heat analysis of the magnetic phase diagram of CeSb