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This chapter presents the theory of laser-induced deformation and patterning of irradiated surfaces. Topics discussed include laser irradiation and thin film deformation, laser-induced temperature distribution, vacancy dynamics in strained crystals, deformation equations for thin films, variational principle for the free energy, deformation instability and surface patterning, and the influence of crystal anisotropy and adhesion.

The development of thin films integrated into semiconductor chips allowed for the development of ferroelectric memories with high information density. The old question of how many unit cells are necessary that ferroelectricity, which is a collective phenomenon, does not disappear, thus became important not only for basic physics but also for technology. The film‐thickness dependence of the out‐of‐plane polarization and depolarizing field is presented. It is shown that the retention time due to thermodynamic nucleation of reversed domains imposes a new fundamental size limit for ferroelectric devices that is higher than the critical thickness for the disappearance of ferroelectricity due to depolarizing fields. The Tilley–Žekš model of phase transitions in thin films is discussed and the polarization profiles are presented. The effect of film thickness on the misfit strain induced magnetoelectric coupling is also treated.

This chapter discusses two important applications of non-single crystal semiconductors: photovoltaic solar cells and large screen liquid crystal display. The electrical and optical properties of polycrystalline and amorphous semiconductors are described. Grain boundaries play a major role in determining the behaviour of polycrystalline materials, acting as energy barriers to current flow and as trapping centres for minority carriers. Grain size and doping levels work together with barrier heights to control material properties. Amorphous materials are characterised by lack of order, but can function as semiconductors with low carrier mobilities. Amorphous silicon, containing hydrogen (aSi:H) is used to make thin film transistors, acting as switches at each pixel point in a LCTV display, thus facilitating matrix addressing. It is also used to make cheap solar cells. Crystalline silicon dominates the commercial field of PV solar cells, but is under challenge from a number of polycrystalline materials, such as CdS:CuInSe.

Sample holders provide uniform and stable temperature control of the sample; eliminate sample stress due to differential thermal contraction between the sample and holder; minimize noise from induced voltages and magnetic pickup by keeping the effective voltage-tap loop area as small as possible; provide well-designed current and voltage contacts, with enough space between each current contact and the nearest voltage lead to ensure that the current distribution is uniform in the region between the voltage taps; and provide firm mechanical support for the sample, particularly for critical-current measurements where large, magnetic Lorentz forces are a major issue. This chapter considers each of these factors in turn, for both bulk sample holders and thin film sample holders, along with examples and design techniques. It also considers the general nature of four-lead measurements, since this technique determines the overall design of most transport-measurement sample holders.

This chapter lays the foundations of operation of both unipolar and ambipolar organic thin film transistors (OTFTs). Thin film transistors are used in display back planes, digital circuits, memory addressing elements, and photodetection. The discussion describes basic transistor principles and the limitations to their performance. Transistor noise and circuit noise margin, cutoff frequency, transconductance, and gain are discussed. Several different lateral architectures including top and bottom gate, and split gate configurations, as well as vertical transistors are described. High performance OTFT materials and channel morphologies and how they are achieved along with contact patterning are discussed. Phototransistors are introduced, and their characteristics are compared with other photodetectors discussed in Chapter 7. Transistor stability and its implication for circuit performance are detailed. Finally, several circuit applications with particular focus on chemical and medical sensing, and communications are described.

The parallel alignment of dipoles in a ferroelectric is due primarily to a relatively strong long-range interaction along the polar c-axis and a weaker shorter-range interaction normal to the axis. Physically this comes about because for electric dipolar forces the parallel alignment is energetically favourable for an isolated pair of c-axis dipoles but not for an isolated pair of dipoles normal to the polar axis. Theoretical and experimental estimates can be made of a correlation range, or distance over which near-neighbour-cell polar displacements are strongly correlated in some sense. This chapter deals with ferroelectric thin films and ceramics such as semiconducting ceramics, optical ceramics, and semiconducting ceramics, the grain boundaries of ceramics, effect of impurities on ceramics, and metastable polarization in ferroelectric materials such as electrets, liquid crystals, and pyroelectric polymers.

This chapter presents a collection of new examples taken from different branches of science. The first examples come from fluid dynamics, starting with the well-known model of viscous droplets spreading by gravity. It then covers topics relating to underground flows important in water management or oil recovery. Attention is given to models of plasma physics. The limits of particle models is also discussed.

When a polymer is constrained to spatial dimensions less than roughly 100 nm, its glass-transition temperature often becomes lower than T_g for the bulk state. This effect is well established for free-standing films and often occurs with supported films and material confined within nanopores. The mechanism for the T_g reduction appears to be the enhanced mobility of surface molecules, a result of fewer intermolecular constraints and greater unoccupied volume. However, this explanation cannot account for many details of the phenomenon—the magnitude of the effect depends on the nature of the confining surface, the chemical structure and even tacticity of the material, and its molecular weight. This chapter reviews how spatial confinement affects segmental and chain mobilities, showing how the effects can be dramatic, yet are complex and unaccounted for by any model.

This chapter presents a review on the recent progress in transmission electron microscopy (TEM) studies of ferroelectric DWs in one of the most widely studied ferroelectric systems — BiFeO3 thin films. This system has been chosen representative for a much wider range of ferroelectric perovskites with functional DWs, due to its strong spontaneous polarization, coexistence of ferroelectricity, ferroelasticity and antiferromagnetism, and numerous functionalities at the DWs. Here, the chapter first briefly introduces the instrumentation, experimental procedures, imaging mechanisms, and analytical methods of the state-of-the-art TEM-based techniques. The application of these techniques to the study of DW structures and switching behaviors is demonstrated, with particular emphasis on the critical roles of interfaces and defects, and interplay between different types of DWs. The phenomena and mechanism discovered in the model system of BiFeO3 are also applicable to many other ferroelectric materials with similar DW structures. The results not only advance the fundamental understanding of static and dynamic properties of ferroelectric DWs, but also form the basis for designing of practical ferroelectric-DW-based devices.

DC and finite frequency transport measurements of thin films of amorphous indium oxide that were driven through the critical point of superconductor-insulator transition by the application of perpendicular magnetic field are presented. The observation of non-monotonic dependence of resistance on magnetic field in the insulating phase, novel transport characteristics near the resistance peak and finite superfluid stiffness in the insulating phase are all discussed from the point of view that suggests a possible relation between the conduction mechanisms in the superconducting and insulating phases. The results are summarized in the form of an experimental phase diagram for disordered superconductors in the disorder-magnetic field plane.

This chapter focuses on technological compatibility of HTS cuprates and progress made in their thin-film technology and conductor development for practical applications. In order to realise a high J_c(77 K) > 1010 A m⁻², deposited HTS films have to be grown with biaxial texturing on suitable single-crystalline substrates. For conductor development, this clearly involves the seemingly impossible task of achieving the required epitaxial growth of HTS films over several kilometre lengths of the metallic substrate. The state of the art of synthesising HTS films using physical and chemical deposition methods is presented and novel techniques for producing unusual multilayer architectures of long HTS conductors are described. The development and present status of first-generation BSCCO conductors are discussed and novel strategies pursued with second-generation coated conductors of YBCO and other potential HTS are presented. The second-generation YBCO conductors have already reached a practical level of their technical applicability.

A theory of the electrocaloric effect is presented. It is shown that the electrocaloric effect in ferroelectrics is maximal at the electric‐field‐induced first‐order phase transition, whereas it is maximal in relaxors at the electric‐field‐induced critical end point. The maximum efficiencies ΔT/ΔE and ΔS/ΔE for various samples are presented. It is shown that in relaxors a giant electrocaloric effect takes place at the critical end point where also the electromechanical response is largest. A universal expression for the maximum temperature change in the saturation regime is derived that is valid both for electrocaloric and magnetocaloric systems.

This chapter discusses the properties of ³He surfaces and its interfaces with other substances. It presents a selection of experiments and their interpretation is made under six headings: restricted geometry, surface tensions, nucleation, thermal boundary resistance, wetting transitions, and thin films.

This chapter presents an overview of significant insights or contributions to modelling provided by three-dimensional dislocation simulations. Four main domains are concerned. A connection has been established between elementary dislocation–dislocation interactions and strengthening mechanisms at the scale of bulk specimens. Simulations of dislocation interactions with point defects and small clusters are now reaching maturity. Simulations of precipitation strengthening are quite accurate, and this domain deserves more attention. Large-scale simulations provide unique insights into collective dislocation processes. The areas concerned are dislocation avalanches, dislocation patterns in monotonic and cyclic deformation, dislocation-based continuum modelling and deformation at high strain rates. The understanding of size effects in small-scale materials—in particular, epitaxial semiconductor layers, thin metallic films and micro- and nanopillars—has improved continuously through a synergy between experiment, simulations and modelling. The chapter closes with a short prospective.

The origin of ferroelectricity in liquid crystals and the basic physical properties of the systems are briefly discussed. Special attention is paid to elementary excitations in ferroelectric liquid crystals, i.e. the symmetry recovering Goldstone mode, the amplitudon mode and the symmetry‐breaking soft mode. The phase diagram of ferroelectric liquid crystals in magnetic and electric fields is presented and the field‐induced Lifshitz point is discussed. The difference in the soliton structure in electric and magnetic fields is presented. The properties of freely suspended smectic thin films are shown as a function of the number of smectic layers involved. This represents an example of the cross‐over from the 3D to 2D universality class.

In this chapter we introduce the relevant energy terms to determine the formation of domains. The regions of transition separating one domain from the next are classified as Bloch, Néel, or cross-tie domain walls. We then analyze domain structures based on energy considerations and demonstrate their utility for simple structures such as particle and films. However, every domain configuration is one of many possible metastable states and which one is realized in practice depends on the magnetization history. The Stoner–Wohlfarth (S–W) coherent rotation model describes the magnetization reversal and hysteresis of an ensemble of small particles. This model, which shows that their coercive field is ideally equal to the anisotropy field, has great practical utility and is discussed further in §9 and §11. Two effective approaches to understanding the process of magnetization and its reversal are coherent rotation and alternatively, a simple potential energy approximation involving the movement, pinning, and de-pinning of domain walls. Finally, the magnetization behavior as a function of the magnetic field, has a simple functional form at both low and high field values. Broadly, domains are expected in the size range 1 nm−10 μm. Techniques for observing and modeling them are discussed in the next chapter.