New Kinds of Phase Transitions: Transformations in Disordered Substances


Book Description

Phase transitions are involved in phenomena ranging from the initial stages of the creation of the Universe to the existence of biological objects. It is natural to as whether any phenomena analogous to phase transitions are possible in disordered substances like liquids and glasses. The possibility of such transitions is still very much a matter of debate. Neither the nature nor the features of transformations in liquids and glasses are yet clear, nor is the nature of the order parameters. Investigations in recent years have shown that transformations in liquids and glasses lead to a drastic change of their physical properties and short-range order structure. The papers collected here contribute to a better understanding of the physics of disordered systems and phase transformations in them. An unambiguous identification of transitions in liquids and glasses requires further high-precision experimental study of the thermodynamic and structural properties in the vicinity of transitions in order to test existing theoretical models and develop new, more accurate ones.




Liquids Under Negative Pressure


Book Description

It is possible to "stretch" a liquid and, when suitably prepared, liquids are capable of sustaining substantial levels of tension, often for significant periods of time. These negative pressure states are metastable but can last for days - long enough for substantial experimental investigation. This volume is a review of recent and current research into the behaviour of liquids under negative pressure. Part I deals with the thermodynamics of stretched liquids. Part II discusses the physical and chemical behaviour of liquids under negative pressure. Part III contains papers on the effect of negative pressure on the solidification of a liquid. Part IV is devoted to stretched helium and Part V discusses cavitation in various stretched liquids. Part VI deals with the effect of foreign substances on cavitation.







Phase Transitions in Solids


Book Description




Carbon at High Temperatures


Book Description

This book deals with the properties and behavior of carbon at high temperatures. It presents new methods and new ways to obtain the liquid phase of carbon. Melting of graphite and the properties of liquid carbon are presented under stationary heat and pulse methods. Metal like properties of molten graphite at high initial density are indicated. A new possible transition of liquid carbon from metal to nonmetal behavior much above the melting point is mentioned. Methodical questions of pulse heating, in particular the role of pinch-pressure in receiving a liquid state of carbon, are discussed. The reader finds evidence about the necessity of applying high pressure (higher than 100 bar) to melt graphite (melting temperature 4800±100 K). The reader can verify the advantage of volume pulse electrical heating before surface laser heating to study the physical properties of carbon, including enthalpy, heat capacity, electrical resistivity and temperature. The advantages of fast heating of graphite by pulsed electric current during a few microseconds are shown. The data obtained for the heat capacity of liquid carbon under constant pressure and constant volume were used to estimate the behavior at temperatures much higher 5000 K.




Disorder and Strain-Induced Complexity in Functional Materials


Book Description

This book brings together an emerging consensus on our understanding of the complex functional materials including ferroics, perovskites, multiferroics, CMR and high-temperature superconductors. The common theme is the existence of many competing ground states and frustration as a collusion of spin, charge, orbital and lattice degrees of freedom in the presence of disorder and (both dipolar and elastic) long-range forces. An important consequence of the complex unit cell and the competing interactions is that the emergent materials properties are very sensitive to external fields thus rendering these materials with highly desirable, technologically important applications enabled by cross-response.




Reconstructive Phase Transitions


Book Description

This book deals with the phenomenological theory of first-order structural phase transitions, with a special emphasis on reconstructive transformations in which a group-subgroup relationship between the symmetries of the phases is absent. It starts with a unified presentation of the current approach to first-order phase transitions, using the more recent results of the Landau theory of phase transitions and of the theory of singularities. A general theory of reconstructive phase transitions is then formulated, in which the structures surrounding a transition are expressed in terms of density-waves, providing a natural definition of the transition order-parameters, and a description of the corresponding phase diagrams and relevant physical properties. The applicability of the theory is illustrated by a large number of concrete examples pertaining to the various classes of reconstructive transitions: allotropic transformations of the elements, displacive and order-disorder transformations in metals, alloys and related structures, crystal-quasicrystal transformations.




Physics of New Materials


Book Description

Physics of New Materials starts from basic science, specially solid-state physics, and then moves into the research and development of advanced materials. The emphasis of the discussions is concentrated on the electronicand atomic structures and properties of transition-metal systems, liquidand amorphous materials, the nano-phase materials, layered compounds, martensite and other structural-transformed materials, and ordered alloys. Though these discussions, the physical aspects and principles ofnew materials, such as strong ferromagnetic alloys, shape memory alloys, amorphous alloys, ultra-fine particles, intercalated layered compounds, deformable ceramics, and nuclear-physics techniques. In addition to these theoretical treatments, modern experimental techniques, exemplified by M|ssbauer spectroscopy and electron microscopy, demonstrate the vast scope of schemes needed in the development of new materials.




Frustrated Materials and Ferroic Glasses


Book Description

This book provides a comprehensive introduction to ferroics and frustrated materials. Ferroics comprise a range of materials classes with functionalities such as magnetism, polarization, and orbital degrees of freedom and strain. Frustration, due to geometrical constraints, and disorder, due to chemical and/or structural inhomogeneities, can lead to glassy behavior, which has either been directly observed or inferred in a range of materials classes from model systems such as artificial spin ice, shape memory alloys, and ferroelectrics to electronically functional materials such as manganites. Interesting and unusual properties are found to be associated with these glasses and have potential for novel applications. Just as in prototypical spin glass and structural glasses, the elements of frustration and disorder lead to non-ergodocity, history dependence, frequency dependent relaxation behavior, and the presence of inhomogeneous nano clusters or domains. In addition, there are new states of matter, such as spin ice; however, it is still an open question as to whether these systems belong to the same family or universality class. The purpose of this work is to collect in a single volume the range of materials systems with differing functionalities that show many of the common characteristics of geometrical frustration, where interacting degrees of freedom do not fit in a lattice or medium, and glassy behavior is accompanied by additional presence of disorder. The chapters are written by experts in their fields and span experiment and theory, as well as simulations. Frustrated Materials and Ferroic Glasses will be of interest to a wide range of readers in condensed matter physics and materials science.