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The 2003 Conference on Dielectrics for Emerging Technologies was organised by the Institute of Physics Dielectrics Group as one of the participating conferences at the IOP Physics Congress held at Heriot-Watt University between 23 and 27 March 2003. This was the second annual conference of the new Dielectrics Group, which was formed from the former Dielectrics Society in October 2001. The conference policy remains unchanged, with the Group adopting an interdisciplinary and broadband approach to studies of the interaction of electromagnetic fields with materials. This policy is well exemplified by the papers that were delivered at this conference.

The aims of the conference were three-fold: to provide a forum for the presentation of leading-edge research on emerging electromagnetic materials, to present developments on the use of dielectrics in emerging technologies and to broaden the debate on metamaterials in the UK, especially in relation to their potential applications. The metamaterials of interest here are macro- or meso-scopically structured materials that offer novel modes of electromagnetic field interaction, thereby widening the range of effective dielectric properties available to us for novel technological applications. They include `negative refractive index materials', `left handed materials', `photonic' or `electromagnetic band-gap materials' and actively-controlled or `smart' electromagnetic materials. Significant metamaterial applications are anticipated in the development of `perfect' lenses, filters, wavefront-conditioning layers and in improved metrology. The conference focussed additionally on dielectrics in support of electronics, photonics and optics, nano-materials, composites and structures, and the development of tuneable dielectrics and resonators for future applications in telecommunications.

We are pleased to report that the conference was successful in achieving its objectives, thirty-four oral papers were delivered and twenty-three poster papers presented, many of which provoked significant debate. All contributions and the vigorous discussions held in this predominantly international forum testify to the health and vigour of this branch of materials physics and engineering. We were particularly pleased on this occasion to have the opportunity to run joint conference sessions with the `Structured Optical Materials' and `Electrostatics' conferences, which were run in parallel at the Congress. Electromagnetic materials science is inherently a cross-spectrum discipline and these sessions demonstrated the considerable overlap of technical interests and research from DC to optical frequencies.

We are delighted to have the privilege of presenting eleven of the papers from the conference in this special cluster of Journal of Physics D: Applied Physics. Between them they capture the wide range of topics that were covered at the conference.

The field of dielectric materials characterisation was well represented and amongst many other topics it included the study of nano-composites, represented here by the papers of Pelster et al and Hussain et al. Composite dielectrics at all scales lie at the centre of most new research into emerging applications and the paper by Bowler and that of Tuncer are also concerned with the understanding and characterisation of such materials. The understanding of the nature and distribution of space charge has always been a core dielectric study and a contribution to this field is made here by the paper of Marat-Mendes et al. Processing is a major factor that governs the properties of all dielectric materials---but this is particularly true in the case of sintered low-loss ceramics. The paper of Pullar et al adds to our knowledge in this important area. The remit of the conference led to the discussion of a very wide range of potential applications. One such is the use of dielectrophoretic forces for separating particles in suspensions (e.g. in pharmaceutical and diagnostic applications). The paper by Flores-Rodriguez and Markz presents a study on one aspect of this discipline. Presentations on meta- and structured materials at the conference are represented here in two papers: those of Shamonina and Solymar and of Zhou, Chan and Sheng, while a study in the closely allied area of band-gap materials is presented in the paper by Schuster and Klein. The final paper from the conference in this special cluster is concerned with an end-use application: the use of tuneable dielectric resonators in base-stations for future mobile telecoms networks. The paper by Krupka et al describes a magnetic approach to such tuning.

In the longer term we sincerely hope that both the conference and these papers will prove to have made a significant contribution to the development and uses of dielectrics, and their metamaterial derivatives, in advanced technological applications. It is noteworthy that as a result of the success of this conference, the 2004 annual conference will be on the subject of `Dielectrics at Meso- and Nano-Scales'. We would like to take this opportunity to express our sincere thanks to all who participated in the conference for their contributions and we would like to express our particular thanks to the authors of the papers in this special cluster of Journal of Physics D: Applied Physics.

We have studied the correlation between microstructure and effective material properties using colloidal dispersions of magnetic nanoparticles in a carrier liquid (ferrofluids). Their microstructure can be altered in a continuous and reversible way via an external magnetic field. Two-dimensional small angle x-ray scattering and Monte Carlo simulations show that field-induced structural anisotropy develops due to the formation of anisometric particle clusters having a preferred orientation parallel to the field. In this polydisperse system particles of all sizes take part in cluster formation. The structural data are compared with results of dielectric measurements in the frequency range from 5 Hz to 1 GHz. We show that dielectric anisotropy is correlated with the shape anisometry of oriented clusters.

Charged particle colloids typically consist of particles with negative surface charge suspended in an aqueous electrolyte solution. A layer of ions forms around each particle, and previous research has shown that the dynamics of this charge distribution, induced by an external field, lead to effective and potentially useful dielectric properties (Lyklema J and Van Leeuwen H P 1999 Adv. Colloid and Interface Sci.83 33, O'Konski C T 1960 J. Phys. Chem. 64 605). Charged nanoparticle colloids are potentially of great benefit because they are extremely stable and their small dimensions make them highly versatile. Possible uses include electromagnetic shielding devices and medical applications. This research focuses on the dielectric properties of charged polystyrene nanoparticle colloids, which are investigated across a range of radio and microwave frequencies. The results show two distinct regions in the permittivity behaviour. The first is the dipolar relaxation of water at microwave frequencies. The second is a high amplitude, low frequency relaxation due to the diffusive motion of ions in the bulk electrolyte beyond the double layer. Effective control of the resulting dielectric response is demonstrated with particle size ranging from 20 to 220 nm. It is shown that the small nanoparticle sizes lead to faster relaxation times than those expected from conventional micron particle sizes, such that the loss extends to microwave frequencies. The results are fitted to a model where the zeta potential, ξ, and double layer thickness, κ⁻¹, are used as fitting parameters.

The ability to control the frequency at which a dielectric material exhibits maximum loss (the relaxation frequency) is of interest in telecommunications and radar absorption. A theoretical investigation of the behaviour of the complex bulk permittivity of a composite material with coated, spheroidal filler particles is presented. In the model, the filler particles are replaced mathematically by electric multipole sources located at their centres (Harfield N 2000 J. Mater. Sci.35 5809–16). It is shown how factors such as particle shape, orientation with respect to the applied electric field, thickness of coating and permittivity value of the individual phases influences the bulk permittivity of the composite material. For a composite with coated filler particles, one or two relaxation frequencies may be observed. Employing the theory of Pauly and Schwan (Hanai T 1968 Electrical properties of emulsions Emulsion Science ed P Sherman (London: Academic)), particular attention is paid to the way in which the relaxation frequencies are affected by the material parameters.

Dielectric relaxation in disordered dielectric mixtures is presented by emphasizing the interfacial polarization. The obtained results coincide with and cause confusion with those of the low frequency dispersion behaviour. The considered systems are composed of two phases on two-dimensional square and triangular topological networks. We use the finite element method to calculate the effective dielectric permittivities of randomly generated structures. The dielectric relaxation phenomena together with the dielectric permittivity values at constant frequencies are investigated, and significant differences of the square and triangular topologies are observed. The frequency dependent properties of some of the generated structures are examined. We conclude that the topological disorder may lead to the normal or anomalous low frequency dispersion if the electrical properties of the phases are chosen properly, such that for 'slightly' reciprocal mixture—when σ₁ ≫ σ₂, and ₁ < ₂-normal, and while for 'extreme' reciprocal mixture—when σ₁ ≫ σ₂, and ₁ ≪ ₂-anomalous low frequency dispersions are obtained. Finally, comparison with experimental data indicates that one can obtain valuable information from simulations when the material properties of the constituents are not available and of importance.

The electrical conduction in low-density polyethylene (LDPE) was investigated in the temperature range from 20°C to 95°C and for applied fields up to 12 MV m⁻¹. The objective was to study the effects of the space charge (SC) accumulated in the material on the low and medium field quasi-steady-state conductivity in LDPE. Very long time (a week or longer) isothermal current measurements were carried out to focus on the situation when the SC effects are dominant. Complementary results were obtained using the isothermal discharge current, the final thermally stimulated discharge current and the isothermal final discharge current measurements. The results are explained by taking into account the constraint imposed by the trapped SC on charge injection, trapping and transport processes.

The columbite niobate ceramics ZnNb₂O₆, MgNb₂O₆, CaNb₂O₆ and CoNb₂O₆ have low dielectric losses at microwave (1–10 GHz) frequencies, resulting in Qf values between 40 000 and 90 000 GHz, making them suitable materials for use in dielectric resonator applications. However, their temperature coefficient of resonant frequency (τ_f) values were high, at between −50 and −90 ppm, and the optimum sintering temperatures were found to be between 1150°C and 1350°C. This paper details the doping of these ceramics with 1 wt%V₂O₅, 1 wt% CeO₂, 2 wt% WO₃ and 0.5 wt% CuO, in an attempt to reduce the sintering temperature. It was found that in many cases the dopants also had an extremely beneficial effect upon microwave properties, increasing ε_r, and decreasing τ_f considerably. Although the dopants often had a deleterious effect upon the quality factor (Q), in some cases they caused an increase in Q. Qf values of over 20 000 GHz were often obtained at lower temperatures, even in poorly sintered niobates, and CuO-doped CaNb₂O₆ yielded Qf values in excess of 65 000 GHz. CoNb₂O₆+V₂O₅ or CuO gave 90% sintered and poorly sintered materials with Qf over 10 000 GHz and 25 000 GHz, respectively, at temperatures within low temperature Co-fired ceramic limits.

Addition of amphoteres could be used to improve the levitation and trapping of particles by negative dielectrophoresis. Addition of amphoteric molecules to electromanipulation media increases not only the permittivity of the medium and its viscosity but also its density. To investigate the effect of addition of amphoteres on levitation and trapping by negative dielectrophoresis, the electrokinetic behaviour of latex beads and viable yeast cells (Saccharomyces cerevisiae) was investigated in concentrated solutions of the amphoteric molecules N-[2-hydroxyethyl] piperazine-N'-[2-ethanesulfonic acid] (HEPES) and ε -aminocaproic acid (EACA) using different frequencies and voltages of the applied electrical signal and microelectrodes of different sizes. When using interdigitated electrodes without castellations, latex beads levitated an average of 43% higher when 0.67 M EACA solutions were used and a 54% higher after adding 0.67 M HEPES compared with the levitation heights when no amphoteres were added. Under the same conditions, yeast levitated 78% and 86% higher, respectively. At low voltages and low HEPES/EACA concentrations, the latex particles accumulated in bands between or above the electrodes. However, at the highest voltages and HEPES/EACA concentrations used, the particles formed a network of pearl chains above the electrode arrays. When using electrodes of the interdigitated castellated type of characteristic size 30 µm, latex particles levitated 32% and 40% higher when 0.67 M EACA and HEPES solutions were used in comparison with when no amphoteres were added. At these concentrations, the flow rate needed to dislodge the latex particles from the traps formed by the electric field pattern between the castellations of the interdigitated castellated electrodes was increased by 46% compared with the flow rate needed to achieve this when no amphoteres were added.

The propagation and manipulation of magneto-inductive waves is studied under conditions when there is reflection due to lack of matching, when power is coupled from one waveguide to another, when coupling causes directional properties and when tunnelling occurs between two waveguides. The relationships obtained are compared and contrasted with those occurring in traditional transmission lines.

We describe a systematic finite-difference-time-domain study on the electromagnetic (EM) characteristics of a specific type of planar metallic fractal patterns. These fractals are shown to totally reflect EM waves at a series of frequencies; between any two reflection frequencies there can be total transmission at some particular frequency. We show that both reflection and transmission are induced by local resonances, and develop an effective medium model to reproduce the simulation results. A double stack of 90°-rotated fractals is shown to exhibit absolute band gaps independent of both the polarization and incidence angles. In particular, the size of the band gaps can be significantly enlarged by multilayer stacking, and the fractal sample size can be significantly smaller than the relevant band gap wavelength.

We report on the controlled excitation of line and point defect modes in a two-dimensional hexagonal electromagnetic bandgap structure made of rods of dielectric material (aluminium oxide). We have investigated the coupling from external waveguides to line defects and subsequent coupling to resonant modes by numerical field simulations and experiments at microwave frequencies. We have demonstrated that an impedance matching to external transmission lines can be achieved for a line defect of a certain width. We have furthermore demonstrated that the excitation of localized defect resonances can be tuned by the variation of certain single lattice elements, affecting the transmission behaviour and quality factor of the resonant modes. Finally, the quality factors of the point defect modes are analysed and a possibility of creation of similar structures for the millimetre wave regime is shown.

Electronically tunable dielectric resonators operating at frequencies of about 2 GHz containing axially and circumferentially magnetized ferrite elements have been investigated. Employing axially magnetized ferrites, a 40 MHz tuning range was obtained with Q-factor greater than 3000. For such structures the tuning speed of the order of milliseconds was achieved using helical enclosure of the dielectric resonator instead of a metal cavity. Resonators containing circumferentially magnetized ferrites were constructed whose resonant frequencies can be switched by short current pulses between two stable values that differ in frequency up to 15 MHz.

The magnetic and transport properties of Dy_1−xSm_xMn₆Ge₆ (x = 0.2–1.0) have been investigated using x-ray diffraction (XRD) and magnetization measurements. Analysis of the XRD patterns indicates that the samples with x ⩽ 0.4 mainly consist of the HfFe₆Ge₆-type phase and the samples with 0.6 ⩽ x ⩽ 1.0 mainly consist of the YCo₆Ge₆-type phase (P6/mmm). The lattice constants and the unit cell volume increase with increasing Sm content. The antiferro–ferri–ferromagnetic transition can be observed with increasing Sm content. The samples with x = 0.2 and x = 0.4 order antiferromagnetically at 425 K and 430 K, respectively, and there are the second magnetic phase transitions below 50 K. The sample with x = 0.6, 0.8 and 1.0 become ferri- to ferromagnetically ordered over the whole magnetic ordering temperature range. The corresponding Curie temperatures are 445 K, 450 K and 454 K, respectively. The magnetoresistance (MR) curve of the sample with x = 0.6 in applied magnetic fields of up to 5 T is analysed. The inflexions in the MR–H curves can be interpreted as being due to the influence of the magnetic field on the Fermi surface or due to the competition between the scattering of the magnetic moments and the effect of the Lorentz force on the conduction electrons.

Fe_65.9Cr_11.6Si_7.5B₁₅ amorphous wire was annealed at 520°C for 30 min and pre-magnetized with a positive field of 60 kA m⁻¹. Its quasi-saturated hysteresis M(H) loop, longitudinal susceptibility, χ_L, and circular susceptibility, χ_c, as a function of axial static field, H, were measured. We found the M(H) loop shifted 89 A m⁻¹ in the negative field direction and both χ_L(H) and χ_c(H) exhibited asymmetric distribution with respect to H = 0: χ_L(H > 0) < χ_L(H < 0), χ_c(H > 0) > χ_c(H < 0). The displaced hysteresis loop and the asymmetric χ_L(H) can be explained by the magnetostatic interaction between hard magnetic inclusions and the residual soft matrix, while the asymmetric χ_c(H) is supposed to the different micro-domains structures resulting from this interaction.

Using plasma-based ion implantation, two types of gradient layers have been prepared on 2024 Al alloy. One is prepared by N-implantation then C-deposition, the other adds an interlayer composed of a Ti layer and a Ti–N layer between N-implantation and C-deposition. C-deposition is carried out at various implanting voltages or C₂H₂/H₂ ratios. The composition depth profiles of these layers were characterized by x-ray photoelectron spectroscopy. The structure, morphologies and microstructure of the C layers were studied using Raman spectroscopy, atomic force microscope and transmission electron microscope, respectively. The surface hardness was measured with a Knoop tester and a mechanical property microprobe. The dry ball-on-disc wear tests were performed in ambient air. The gradient layer without interlayer is composed of an N-implanted layer rich in AlN and a diamond-like carbon (DLC) layer (film), and the two layers are connected with a C–Al transition layer containing Al₄C₃. The Ti layer rich in α -Ti and the N-implanted layer are connected by a Ti–Al transition layer containing TiAl₃, while the Ti–N layer rich in TiN and the DLC film are connected by a C–Ti transition layer containing TiC, TiCN, etc. Thus, the gradient layer with interlayers has optimized the gradient structure. DLC films are compact and amorphous, contain high sp³/sp² ratios and depend on the implanting voltage and the C₂H₂/H₂ ratio. Similarly, these gradient layers exhibit significant improvement in morphologies, surface hardness and tribological properties; the interlayer, the implanting voltage and the C₂H₂/H₂ ratio all have prominent effects on these properties.

We demonstrate a tunable-focus microlens array using polymer network liquid crystals (PNLCs). PNLCs were prepared by ultraviolet (UV) light exposure through a patterned photomask. The UV-curable monomer in each of the exposed spots forms an inhomogeneous centro-symmetrical polymer network that functions as a lens when a homogeneous electric field is applied to the cell. The focal length of the microlens is tunable with the applied voltage.

The humidity-voltaic effect, i.e. generation of open-circuit voltage (V_oc), in Au–porous silicon (PS) interface in humid atmosphere (up to 450 mV at 95% relative humidity) in dark and daylight illumination is discovered. The humidity-stimulated voltage generation is attributed to the splitting of water and hydrogen molecules on the surfaces of the Au catalyst, where further diffusion penetration of hydrogen ions into the Au–PS interface results in the formation of dipoles, thus inducing V_oc across dipoles. The generation of V_oc (up to 550 mV) has also been observed on dipping of Au–PS structures in different hydrogen-containing solutions (ethanol, benzine, sodium tetraborate pentahydrate, etc). Data of response time-dependent changes of the open-circuit voltage generated in Au–PS structures under humid conditions were used for the estimation of diffusion coefficients of hydrogen. The temperature dependence of the diffusion coefficient of hydrogen at 323–353 K via the pore surfaces of PS is attributed to be D = 1.3 × 10⁻²exp (−0.25/kT).

The mass preparation of SnO₂ nanobelts and nanowires has been achieved by carrying out the reaction of SnO₂ powder and graphite at 1150°C. A metallic catalyst and vacuum conditions are not necessary. The temperature of the substrates and the concentration of oxide vapour were the critical experimental parameters for the formation of different morphologies of SnO₂ nanostructures. The as-synthesized SnO₂ nanobelts formed in region II are single crystalline with a [101] growth axis, with widths ranging from 50 to 500 nm, width-to-thickness ratios of 5–10, and lengths up to a few millimetres.

Hexagonally well-faceted ZnO nanowire arrays were successfully aligned to Si wafers using a metal-catalyst-free physical vapour deposition method at 500°C. The ZnO nanowires prepared using the metal-catalyst-free approach are single-crystalline and of high-purity. The one-dimensional growth of these nanowires with an average diameter of 100 nm follows the c axis direction of wurtzite ZnO. The as-synthesized nanowire arrays on Si wafers could offer novel opportunities for both fundamental research and technological applications.

In this work, the inter-relationship between the microstructure, the grain boundary electronic structure, and the high- and low-field electrical properties of the positive temperature coefficient of resistivity BaTiO₃ ceramic thermistors was explored. At high temperatures, the resistance of the material is strongly dependent on the field strength. This is an intrinsic feature of the double Schottky barrier structure of the grain boundaries. Low resistivity thermistors (ρ ≈ 10–100 Ω cm) were prepared by standard ceramic processing routes. Low-field properties show a large resistivity jump starting at temperatures above 130 °C. The resistivity under high fields (up 1 V per grain boundary, V_gb) was measured in the insulating state at elevated temperatures (180 °C < T < 220 °C). High-field data displayed good agreement with the model for transport, dominated by thermionic emission. It was also observed that the combination of grain boundary dopants (e.g. Mn) and high doping levels (La concentration ⩾0.35 mol%) significantly improved the high-field resistance at the cost of an increase in the room temperature resistance. In addition to grain size effects, this behaviour was attributed to the presence of deep-level grain boundary states caused by the presence of Mn.

We aim here to describe electromigration-induced interconnect failure using a one-dimensional microstructure model (already one-dimensional models are used for the stress evolution). One might expect such a model to be reasonably successful because either (i) line widths are well below grain-boundary diameters (e.g. in as-patterned aluminium) or (ii) sidewall or topside surfaces provides the dominant diffusion path (e.g. in post-pattern annealed aluminium or copper). Our simple model is based on the Theory of Runs from probability theory and consequently may be solved analytically. As a test, we demonstrate that the model is able to reproduce the cluster length statistics of the two-dimensional simulator MIT/EmSIM for narrow metal (near-bamboo) stripes to a very good approximation. The importance of developing such a model is that, because of its analytical nature, it may access important areas where statistics are difficult for the simulator, such as rare events—e.g. time-to-first-failure rather than average events such as the mean-time-to-failure—or impossible events such as σ_d ≠ 0.27. In addition, it should allow some light to be thrown on the validity of the failure-unit model used to obtain interconnect lifetimes.

We measured the density normalized ionization coefficients and attachment coefficients in diluted c-C₄F₈/Ar mixtures and in pure perfluorocyclobutane (c-C₄F₈) by the steady-state Townsend method. The ionization coefficients in the mixture gas are almost equal to those in pure argon at the high E/N range but differ considerably at the low E/N range. The present coefficients in pure c-C₄F₈ agree well with previously reported values at the high E/N range, but there are significant differences at the low E/N range. Measurements in the low E/N range were difficult, and there are few data of the attachment coefficients.

In this work, a large area microwave plasma reactor is used, in which a rf-biased substrate is exposed to argon plasma. A directional energy analyser mounted in the substrate holder was used to measure ion energy distribution functions in argon plasma. It was found that a resonance behaviour between ion transit motion and the substrate rf-bias oscillation yielded important enhancement of ion energy when the rf-bias and ion plasma frequencies reached roughly the same values.

An Ar thermoelectron-enhanced microplasma (TEMP) jet was characterized by spectroscopic study. The 1s₅ lowest metastable densities at the core of the plasma and very close to the substrate, about 4 mm apart from the torch, were obtained successfully using laser absorption spectroscopy (LAS) and laser induced evanescent-mode fluorescence spectroscopy (LIEF). For TEMP generated with 450 MHz, 5 W and 60 Torr, these densities were estimated to be about 3 × 10¹² cm⁻³ and about 10¹⁰ cm⁻³, by the LAS and LIEF methods, respectively. Moreover, gaseous temperature was also estimated as about 700 K by the LAS method. Depopulation of the 1s₅ metastable atoms might be caused primarily by gaseous diffusion between the torch and the substrate. Finally, we report a device with a TEMP generator at the top of a flexible fibre called the 'plasma fibre', which allows plasma processing in any location, as with laser processing using an optical fibre.

This article was due to be published in issue 23 of 2003. To access this special issue, please follow this link: http://www.iop.org/EJ/toc/0022-3727/36/23

The discharge behaviour of metallic cylinder-dielectric plane gaps in flowing helium was examined under atmospheric pressure at a frequency of 10 kHz as a function of gap length and applied voltage. The high-voltage electrode consisted of a steel cylinder with a radius of 3.15 mm, with alumina (Al₂O₃) or glass plates being utilized as low-potential electrodes. The bottom surface of the low-potential electrodes was covered with a thin Al layer (alumina plate) or an ITO layer (glass plate) that formed the grounded counter-electrodes. The electrical and photoemission currents were recorded simultaneously and precisely synchronized with an ultra-high-speed intensified charge coupled device camera for recording the discharge patterns. The experimental results were compared with those derived from a mathematical model on the basis of the continuity equations for electrons, ions and excited particles and the Poisson equation. The influence of surface charge on the dielectric electrodes on the time evolution of the helium discharge was analysed, and the experimental and theoretical vertical (y(t)) and horizontal (x(t)) dimensions of the discharges were determined for different low-potential electrode arrangements. A reasonable agreement was obtained between the measured and calculated y(t) and x(t) values.

Using small angle x-ray scattering, we have investigated the effects of polyvinylpyrrolidone (PVP) and oleic acid (OA) on the structures of the cubic phase of 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE) films. At lower PVP concentrations, DEPE–PVP mixed films existed in two cubic phases. With increasing PVP concentration in the DEPE–PVP mixed phase, a phase transition from Q²²⁹ (Im3m) to Q²²⁴ (Pn3m) occurred. The effect of addition of OA to a DEPE–PVP mixed phase was also determined using a certain fixed amount. At 0.5 mol% OA, the presence of low amounts of OA allows the DEPE–PVP–OA system to organize in a cubic Q²²⁹ phase. At 1.0 mol% OA, the presence of larger amounts of OA induces formation of coexisting Q²²⁹ and Q²²⁴ phases. At 1.5 mol% OA, the presence of even larger amounts of OA promotes formation of a cubic Q²²⁴ phase in the DEPE–PVP–OA mixture.

The processes in the synthesis of iron silicide thin films (FeSi and FeSi₂) on a single-crystal Si substrate implanted with different doses of Fe⁺ ions (D = 10¹⁵–2 × 10¹⁷ cm⁻²) and subjected to pulsed laser annealing (λ = 0.69 µm, τ = 80 ns, W = 0.6–1.4 J cm⁻²) are investigated. Using x-ray diffraction, transmission electron microscopy and Rutherford backscattering spectrometry, the structure and phase composition of the synthesized films and the depth profile of Fe atoms in the Si are studied. It is shown that laser annealing (W = 0.6–1.1 J cm⁻²) of high-dose implanted Si (D > 10¹⁷ cm⁻²) results in the formation of epitaxial iron monosilicide (FeSi) layers. Increasing the pulse energy up to 1.4 J cm⁻² leads to a redistribution of Fe atoms in the Si and formation of a mixture of silicide phases (FeSi+FeSi₂) with the cellular structure of a synthesized layer. In the case of low-dose implanted Si (D ∼ 10¹⁶ cm⁻²), the formation of cellular structures takes place at lower energy densities (W ∼ 0.8 J cm⁻²), with segregation of Fe atoms to the Si surface.

High-energy electron-irradiated poly(vinylidene fluoride–trifluoroethylene) 56/44 mol% copolymers are studied in a broad dose ranging from 0 to 110 Mrad. The experimental results are obtained by differential scanning calorimetry (DSC), x-ray diffraction, dielectric constant, dc conductivity and polarization hysteresis loop based on structural changes and dielectric relaxation behaviour. All the x-ray and DSC results show that both the crystalline and polar ordering decreased after irradiation, indicating a partial recovery from trans–gauche bonds to local trans bonds (polar ordering). The dielectric relaxation peaks, obeying the Vogel–Fulcher Law, indicate that the copolymers have transformed from a normal ferroelectric to a relaxor ferroelectric. It is also found that dc conductivity can be modulated with electron irradiation, as well as the hysteresis loop characteristics.

A comparative study of the unit cell parameters and volume of the chalcopyrite-related ordered defect compounds and other In-rich phases of the Cu–In–Se ternary system is made. These compounds fall on the tie-line of (Cu₂Se)_{1 − x}(In₂Se₃)_x. It is found that the unit cell parameters and volume of the compounds that can be derived from the formula Cu_{n − 3}In_{n + 1}Se_2n, where n = 4,5,6,7,8 and 9, decrease with an increase in the fraction of cation vacancies to the total number of cation positions, m, or interacting donor–acceptor defect pairs per unit l in the chemical formula. The reduction in the unit cell dimensions is explained as due to the decrease in the effective cation radius caused by the increase in m or l. This behaviour is consistent with Vegard's law. However, the unit cell parameters of other In-rich phases such as CuIn₄Se₆ and CuIn₄Se₇ reported in the literature do not follow this trend. It must be noted that with indium having a 3+ oxidation state, the formation of these materials can only be explained if the valence of Cu atoms is 0 and 2+, respectively, different from the 1+ expected for the members of the Cu₂Se–In₂Se₃ system.

Eddy-current induction by an air-cored coil located inside a long cylindrical bolthole in an isotropic conductive medium is examined using a second-order vector potential formalism. Closed-form expressions are presented for (i) the induced electromagnetic fields and currents, and (ii) the change in coil impedance, ΔZ, due to eddy-current induction in the surrounding conductor. In these expressions, the coil characteristics enter via a source function, D_s. Two alternative methods for computing D_s are described: in one, D_s is computed directly, and in the other, D_s is computed using a knowledge of the source magnetic flux density at the surface of the hole. The strengths and weaknesses of the two approaches are discussed. The non-axisymmetric case of a cylindrical coil with its axis perpendicular to the hole axis is examined in detail because of its significance in eddy-current non-destructive evaluation using bolthole probes. An explicit closed-form expression for ΔZ in terms of the coil and bolthole parameters is derived for this important geometry. The validity of the theoretical calculations was tested by comparing the theoretical results with experimental measurements of ΔZ as a function of frequency for a series of air-cored coils inside 10.0 and 6.4 mm diameter boltholes in Al alloy specimens. The theoretical and experimental results are in excellent agreement.

This study deals with the nucleation mechanism of electric explosion of wires allowing estimation of wire parameters at the start of the explosion for a wide range of experimental conditions. We analyse the dependence of the limit value of the energy deposited during the initial resistive phase of heating of the wire on the parameters of the wire and circuit as well as the size distribution of metal particles formed on electrical explosion of the wire. We discuss the correspondence of these results with previously published experimental data.

Nuclear reaction analysis using a ¹²C(d, p₀)¹³C reaction and a ¹⁶O(d, p₁)¹⁷O reaction, with 1.02 MeV deuterons in an accelerator microprobe, has been used to produce quantitative linescans of the carbon and oxygen levels in ex-service ethylene pyrolysis tubes of HPM, HK40 and Manaurite XM alloy. Particle induced x-ray emission in the ion beam microprobe and energy dispersive analysis of x-rays in a scanning electron microscope were used for linescans of the heavier elements (Cr, Ni, Fe, Si and Ti). The composition linescans were used to calibrate the response and accuracy of an eddy current probe system for measuring carburization near the inner surface of the tubes. The influence of the ferromagnetic outer oxide surface layers has been clarified. A two-dimensional ANSYS finite element model (FEM) was used for interpretation of the eddy current scans. Good correlation was obtained between the ion beam analysis results, the impedance scans and the FEM.