Table of contents

On 1 January, 2004, I assumed the position of Editor-in-Chief of Journal of Physics D: Applied Physics. I will start by saying that I will do my best to justify the confidence of the journal management and publishing staff in my abilities.

I was fortunate to have been able to work, as an Editorial Board member, with my predecessor, the previous Editor-in-Chief, Professor Allister Ferguson. Allister has provided a high degree of intellectual stewardship for the journal in the last five years. He has made the job appear a worthy challenge for me. I therefore take this opportunity to thank Allister on behalf of the Editorial Board and publishing staff of the journal.

Several other factors contributed to my decision to accept this position. The first is the group of people who actually go about the business of publishing. The Senior Publisher, Nicola Gulley (and her predecessor Sophy Le Masurier); the Managing Editor, Jill Membrey; the Publishing Administrators, Nina Blakesley and Sarah Towell; the Production Editor, Katie Gerrard and their office staff form an amazing group and have managed to make the operation of the journal incredibly efficient. An index of this is the speed with which incoming manuscripts are processed. The average time between the receipt of a manuscript and its web publication, if accepted, is 130 days. This is three to five times shorter than for most other journals. A factor that contributes to this success is a responsive pool of referees that the publishing staff have as a valuable resource. Ultimately, the standard bearers of any journal are the referees. Therefore, a grateful `thank you' is due from all of us at J. Phys. D to all our referees, who diligently perform this honourable task.

The Associate Editors of the journal, Professors Lawler, Margaritondo and O'Grady, also provide immense scientific leadership. They help in defining new directions for the journal and in the publishing process. Last, but not least, a remarkable asset of the journal, and a tremendous intellectual resource, is the Editorial Board. The board members are all distinguished scientists and engineers who provide valuable counsel in defining the technical scope of the journal and its management. The members attend the board meetings at least once a year and, as a dynamic group, discuss ways of making the journal better. Most of them, including myself, also publish in J. Phys. D on a regular basis. This is truly a unique feature.

So, what do I hope to accomplish during my tenure? I will strive to continue the legacy established by Allister and to look at ways of making a first-rate journal even better. At the heart of this is the quality of papers published. This can be done in several ways: raising the bar for refereeing and acceptance, regular publication of topical clusters and special issues in important areas, and publication of review articles by internationally renowned researchers and academics. In all these areas, the Editorial Board members can play a leading role. While I believe that the present topical scope of the journal is adequate and covers the important areas of applied physics, it is easy to miss out on important emerging areas. Therefore, we will have to keep the scope of the journal under constant scrutiny. Above all, the content of the journal must remain relevant at all times.

I look forward to working with the journal's excellent staff, Associate Editors, and the Editorial Board.

Applicability of Fourier transform infrared (FTIR) spectroscopy to an in situ diagnostics tool of plasma–surface interactions is described. After a brief review of conventional reflection absorption spectroscopy (RAS) and phase-modulated RAS (PMRAS), our FTIR phase-modulated spectroscopic ellipsometry (PMSE) is described in detail. The FTIR PMSE is constructed by insertion of a grid polarizer as an analyser in front of an infrared detector in addition to the conventional set-up of PMRAS. This simple change brings about a higher sensitivity than that of conventional PMRAS, which enables us to detect chemical species generated on (or removed from) the top surface layer during plasma processing. This feature is demonstrated by the fact that our FTIR PMSE can be applied to surface diagnostics during reactive ion etching processes such as for Si, SiO₂/Si, SiO₂/Si₃N₄, SiO₂/photo-resist and low-dielectric-constant films.

Magnetic, magneto-transport properties and electronic specific heat coefficient of the Mn₂Sb_0.88Ge_0.12 compound have been studied. A metamagnetic transition from antiferromagnetic to ferrimagnetic, which is induced by an external field, is accompanied with a large negative magnetoresistance (MR) effect. The MR ratio at room temperature is −11% at a magnetic field of 5 T. The field dependence of the MR ratio and the magnetization of the Mn₂Sb_0.88Ge_0.12 compound, together with the electronic specific heat coefficients, confirm that the negative MR effect is originated from the reconstruction of Fermi surface, due to the collapse of the super-zone gap after the metamagnetic transition.

Particulate composites of lead–zirconate–titanate (PZT) and NiFe₂O₄ were prepared using conventional ceramic processing. The measured magnetoelectric (ME) response demonstrated strong dependence on the volume fraction of NiFe₂O₄, the magnetic field, and the angle between the magnetic field and polarization in the ceramics. A large ME voltage coefficient of about 80 mV cm⁻¹ Oe⁻¹ was observed for 0.32NiFe₂O₄/0.68PZT composite ceramic. In particular, at low magnetic fields, the ceramics were found to have a large ME response, linearly varying with both dc and ac magnetic fields.

The results of current–voltage (I–V) characteristics measured at different temperatures in polyethylene (PE) films obtained by our own experiments and the ones extracted from Suh K S et al (2000 J. Appl. Phys.87 7333) are presented. The current depended strongly on temperature, namely, it increased with increase of temperature. The non-linearity in the I–V behaviour was observed at higher voltages. We suggest a phonon-assisted tunnelling model to explain the experimental results. The current mechanism in polymer diphenylaminostyrylbenzene (DASMB) films and in tris(8-hydroxyquinoline) aluminium (Alq₃) films are also discussed.

Ferroelectric Bi_3.25La_0.75Ti₃O₁₂ (BLT) films and LaAlO₃ (LAO) insulator layers for metal/ferroelectric/insulator/semiconductor structure were first fabricated by chemical solution deposition and pulsed laser deposition. LAO films as a buffer layer show an amorphous structure, a relatively high dielectric constant and good electrical properties. Pt/BLT/LAO/n-Si annealed at 650°C exhibit better hysteretic capacitance–voltage characteristics, with a memory window of 1.3 V and extremely low leakage current density. Furthermore, the memory window does not alter with the sweeping rates of the bias voltage. This implies that the Si surface potential has been controlled by the poling charges of BLT. The introduction of a LAO buffer layer prevents the interfacial diffusion between the BLT and Si substrate effectively. Therefore, BLT/LAO/Si is an attractive candidate for ferroelectric field effect transistor applications.

Even though image plate technology is successfully applied in x-ray detection, many questions concerning its detailed functional mechanisms have still not been answered. In this paper it will be shown that a previously suggested non-stoichiometric monophase of BaF_1.12Br_0.88 : Eu²⁺ resulting from the BaF₂/NH₄Br preparation route cannot be supported. It will be demonstrated by x-ray analysis that depending on the starting ratio of BaF₂ to NH₄Br during sintering or the already synthesized BaFBr : Eu²⁺ to BaF₂ during annealing, stoichiometric BaFBr : Eu²⁺ with or without a BaF₂ phase will always be obtained. Furthermore, it will be shown that in the case of a molar stoichiometric starting ratio of BaF₂/NH₄Br, partial sublimation of NH₄Br during sintering can be hold responsible for the appearance of BaF₂ as a second phase. Rietveld refinement is utilized to derive the quantitative amount of the individual phase compositions of BaFBr : Eu²⁺ and BaF₂. In terms of image plate properties, it will be shown that the composition of BaFBr : Eu²⁺ and BaF₂ after the high temperature treatment determines the type of photostimulable colour centre generated during x-irradiation. Finally, the results obtained will be interpreted in terms of published photostimulated luminescence formation models.

Thermoluminescence (TL) and photoluminescence (PL) measurements have been performed on gamma-irradiated amorphous SiO₂ and SiO₂ : Eu glass samples prepared by the sol–gel technique. In this type of silica the basic TL feature i.e. a prominent glow peak at 60 < T_m < 120°C is similar to that already studied in several such amorphous SiO₂ samples. The temperature of the glow peak also shifts to higher values as a result of partial pre-heating treatments as has been reported earlier for other silica glasses. In the europium doped silica a prominent TL peak is obtained at around 170°C with a small shoulder at around 115°C. Significantly, a partial pre-heating for even up to 100°C simply removes the 170°C peak from the glow curve and a new peak of very low intensity is found above 300°C. An explanation for such strange results has been provided in this paper. Moreover, PL studies performed on the europium doped material show the presence of europium as both Eu²⁺ and Eu³⁺ in the material.

Photovoltaic properties of a photovoltaic cell with structure indium–tin oxide (ITO)/ZnO/C₆₀/poly(3-hexylthiophene) (PAT6)/Au have been investigated. The C₆₀/PAT6 heterojunction of this cell was fabricated by spin-coating a chloroform solution of PAT6 onto the C₆₀ thin film formed on ZnO-coated ITO. Fabricated by this method, the photovoltaic cell has demonstrated a high efficiency for solar cells based on organic polymers, i.e. a monochromic external quantum efficiency of over 70% at the peak wavelength and a power conversion efficiency of 1.0% under AM1.5 spectral illumination of 100 mW cm⁻².

A prediction method is proposed for dielectric strengths of hot N₂/O₂ mixtures as well as hot air in the heavy particle temperature range of 300–3500 K. Electrical breakdown in hot gases by application of an electric field occurs more easily than that in cold gases. Such an electrical breakdown in hot gases can be seen in a circuit breaker after arc interruption. First, equilibrium compositions of hot N₂/O₂ mixtures were calculated by means of Gibbs free energy minimization. Second, electron energy distribution functions (EEDF) for the hot mixtures to which electric fields were applied were computed using the derived composition by adoption of the two-term expansion approximation of Boltzmann equation. Third, the ionization coefficient α and the electron attachment coefficient η were calculated from the EEDF obtained. The reduced critical electric field strength (E/N)_cr, which gives zero effective ionization coefficient , was derived for hot N₂/O₂ mixtures as a function of heavy particle temperature. The result indicates that (E/N)_cr decreases with increasing heavy particle temperature from 1500 to 3500 K, which results mainly from NO formations and O₂ dissociations. The predicted result for air was compared with experimental results, and they showed good agreement.

A dusty plasma with positive grain charge can be produced in a Q-machine K⁺ plasma by the addition of SF₆ gas. negative ions replace the plasma electrons, and the dust grains acquire a positive charge, since the K⁺ ions are more mobile than the ions. The excitation by an electric field, E₀, of ion-acoustic and dust-acoustic waves is analysed.

As the Bohm criterion becomes multivalued in electronegative plasmas, when the ionization rate is low, the solution of Poisson's equation consists of an oscillatory electric potential profile before the sheath is formed (stratified presheath). By including the positive ion thermal motion these oscillations may be attenuated. The influence of this thermal motion on the parameter space region in which the stratified presheath takes place in the case of plane geometry is analysed.

The time-resolved measurements of the rotational temperature in a pulsed microwave discharge in nitrogen in the range of pressures from 1 to 100 mbar are performed by means of the spectroscopic study of the rotational structure of the second positive system. The rotational temperature at the steady state ranges from 1000 to 3000 K depending upon the gas pressure. The equality between the rotational and gas temperatures is discussed. The time dependence of the temperature during the pulse is characterized by a fast (100 µs) heating time followed by saturation. The steady-state temperature at 100 mbar is lower than at 40 mbar. The results are analysed with the help of the heat balance equation, and the anomalous behaviour of the gas temperature at higher pressures is discussed. As the BaTiO₃ pellets are added inside the discharge, the gas temperature is reduced by half, which is caused by more effective gas cooling. Moreover, the pellets make it possible to obtain the discharge at pressures up to the atmospheric pressure.

Plasma created during electrical discharge machining is systematically investigated using optical emission spectroscopy. Typical spectra show a strong H_α and continuum radiation, with many lines emitted by impurities coming from electrode and workpiece materials. The dielectric molecules are cracked by the discharge. Changing polarity affects the electrode wear and workpiece erosion rates, which can be qualitatively seen on the spectra. Time-resolved spectroscopy shows that the plasma density reaches 2 × 10¹⁸ cm⁻³ at the beginning of the discharge. This extreme density causes the merging of lines, strong Stark broadening and shift of the H_α line. Afterwards, the density decreases rapidly with time. The electron temperature remains roughly constant around 0.7 eV. The low temperature and the high density measured prove that the EDM plasma is non-ideal (Γ ≃ 0.45). Absence of the H_β line, asymmetric shape of the H_α line and complex structures around H_α are other spectroscopic evidences of the plasma non-ideality.

A two-dimensional numerical model of the interaction between an electric arc and a solid anode of different types is presented in this study. The CFD commercial code FLUENT is used to model the plasma flow and the solid anode domain. Quantities such as the velocities or the temperature are presented, and the energy transfer components between the plasma and the anode are quantified. Comparisons of the calculated results with the available experimental data in the literature show that the model predictions are in good agreement. In the case of argon gas and a copper anode, with the distance between the two electrodes 10 mm, the maximum temperature near the cathode tip is 21 000 K for a current of I = 200 A. For the same configuration, the maximum of the current density in the copper electrode is found to be −2.5 × 10⁶ A m⁻². The electrical flux is the main component of the transferred flux on the anode. Once validated, our model is applied to other theoretical and experimental configurations and allows us to study several parameters when attention is focused on the influence of metal vapour from the vaporization of the anode or the current-carrying path in the electrode on the arc behaviour. According to the current-carrying path in the anode, the current density distribution is affected in the material and its surface.

Quartz crystal microbalances (QCMs) provide sensitive probes for changes at solid–solid or solid–liquid interfaces. It is essential to obtain a physical insight into the details of the interface loading mechanism to interpret the observed behaviour leading to fresh applications of AT-cut quartz resonators. In this work, a mechanical slip model of the interface between a quartz plate and a viscoelastic liquid is presented to replace the continuous displacement assumption. The electrical impedance of a compounded quartz crystal resonator is expressed as a function of the properties of liquid, and the quartz and the strength of contact attraction between the solid and liquid. The interfacial slip parameter between the solid and liquid, which is defined as the displacement transmission from solid particles to liquid bottom particles, is explicitly calculated from the complex attraction strength between the liquid and solid. Comparisons of the physical slip model with other interfacial modes used in the QCM are presented, including the continuous mode and the transmission mode based on the friction force interface. The explicit expression of the slip parameter is presented, and the influence of interfacial slip on QCM measurements is discussed with numerical results. A detailed physical description of the solid–liquid interfacial is useful for exploring fresh ideas for the use of the QCM in biological industry. A new approach by using the slip parameter measured with QCM is proposed to determine the attraction strength between the particles of a viscous liquid and solid particles. The experimental data in the literatures for a hydrophilic-coated sensor and a hydrophobic-coated sensor are used for the numerical examples. It is found that the imaginary part of the interactive strength of these two types of sensor is almost the same. The real part of the interactive strength contributes significantly to distinguish the different interface conditions for these two types of sensor.

Carbon nitride films (CN_x films) were deposited on Si(100) substrates by the electrolysis of methanol–urea solution at high voltage, atmospheric pressure, and low temperature. The microstructure and morphology of the resulting CN_x films were analysed by means of Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometry (FTIR), x-ray diffraction (XRD), and atomic force microscopy. The tribological properties of the CN_x films were examined on an UMT-2MT friction and wear test rig. The Raman spectrum showed two characteristic bands: a graphite G band and a disordered D band of carbon, which suggested the presence of an amorphous carbon matrix. XPS and FTIR measurements suggested the existence of both single and double carbon-nitride bonds in the film and the hydrogenation of the carbon nitride phase. The XRD spectrum showed various peaks of different d values, which could confirm the existence of the polycrystalline carbon nitride phase. The hydrogenated CN_x films were compact and uniform, with a root mean square roughness of about 18 nm. The films showed excellent friction-reduction and wear-resistance, with the friction coefficient in the stable phase being about 0.08. In addition, the growth mechanism of the CN_x films in liquid phase electro-deposition was discussed as well. It was assumed that the molecules of CH₃OH and CO(NH₂)₂ were polarized under high electric field, and the CN_x film was formed on the substrate through the reaction of the –CH₃ and –NH₂ groups on the cathode.

The dielectric properties of the perovskite mixed system La(Mg_1/2Ti_1/2)O₃–BaTiO₃ were studied at radio, microwave and far infrared frequency ranges in respect of potential microwave application. The room temperature values of relative permittivity, dielectric loss and temperature coefficient of the resonant frequency were estimated by different methods. The permittivity and the thermo-stability coefficient were found to follow a simple hyperbolic-type dependence on composition. The dielectric response of air- and oxygen-sintered ceramics was compared and analysed. The origin of the dielectric loss and frequency dispersion in BaTiO₃-rich compositions of the system is discussed.

Barium strontium sodium niobate (Sr_0.7Ba_0.3)₂NaNb₅O₁₅ (SBNN70) crystals were grown by the Czochralski method. X-ray energy dispersive spectrometry showed that SBNN70 crystals have a stoichiometric composition nearly identical to the starting materials. X-ray diffraction of crushed powder indicated that the SBNN70 crystals are orthorhombic with a = 1.2748 nm, b = 1.1402 nm and c = 0.3898 nm. The measured temperature dependence of dielectric constants showed strongly anisotropic relaxor behaviour. The Curie temperature of the SBNN70 crystals is 186.7°C, which is 116°C higher than that of the (Sr_xBa_1−x)₅Nb₁₀O₃₀ (SBN) crystal. The transmissivity and refractive index of [001] oriented SBNN70 single crystals were measured, and a deep energy level of 3.54 eV was found. The SBNN70 crystal has better than 70% optical transmittance for wavelengths above 500 nm. The refractive index of SBNN70 is 2.004 at 632.8 nm, which is lower than 2.3117 for SBN crystals.

We demonstrate theoretically point and linear defects and their combination in nanoscale periodic porous graphite composed of graphite with nanoscale periodic pores. The point and linear defects in semiconducting nanoscale periodic porous graphite cause energy modes in the band gaps. Electrons satisfying these energy modes can exist only at point and linear defects, which indicate the electron localization and guiding, respectively. Point defect modes are discussed in point defects with various rotational symmetry, and linear defect modes are discussed in two kinds of linear defects. Moreover, the conductance of linear defects and the combination of point and linear defects are discussed.

It is shown that resolving doublets from high-resolution gamma-ray spectra using spectrum convolution offers several advantages over the usual peak search techniques that work with the original, non-convoluted spectrum. The spectral lines are approximated by Gaussian shapes with known widths and the convolution function is chosen as a projector which eliminates any linear background from the final results. The proposed method is more efficient compared with the standard method in frequently encountered cases where doublets are embedded within other peaks of the spectrum. Analytical expressions for the uncertainties of peak areas are given.

Lead fluoride chloride (PbFCl) crystal, whose density is about 7.11 g cm⁻³, was grown by the modified Bridgman method. PbFCl can emit violet-blue light with the peaks at 392 and 420 nm when excited by ultraviolet light or x-rays. The light yield of PbFCl under irradiation of ¹³⁷Cs is about 20% as that of bismuth germanate. A fast and a slow decay time with 4 ns and 35 ns, respectively, were obtained when PbFCl was studied with a pulsed x-ray facility. The irradiation resistivity of PbFCl was studied by applying ⁶⁰Co. The results of the experiments indicate that PbFCl is a new inorganic scintillator.

The behaviour of the polymer polyether ether ketone (PEEK) has been investigated under conditions of one-dimensional shock loading. This has involved measurement of the Hugoniot in terms of stress, shock velocity and particle velocity, and measurements of the lateral stress, which have been used to determine the shear strength, and its variation with shock stress. Analysis of the relationship between shock velocity and particle velocity shows a simple linear response, in common with many other materials. Shear strength has also been shown to increase with shock stress, with a break in slope at ca 1.0 GPa. Below this stress, the material appears to behave in a simple elastic manner, which suggests a Hugoniot elastic limit of 1 GPa. Shear strength has also been observed to increase significantly behind the shock front both above and below 1 GPa. This behaviour has been observed in other polymeric materials, where it was suggested that these materials were responding by a viscoplastic mechanism.

The high sensitivity of the electron work function (EWF) to surface condition has attracted increasing interest from materials scientists. In this study, application of a Kelvin probe, which is used to measure the EWF, for determination of the material's yielding under multiaxial plane stresses was explored. Yielding of copper was investigated using the EWF as an indicator of plastic deformation. It was demonstrated that the yield point of copper determined using this method was consistent with those given respectively by von Mises and Tresca yield criteria. Furthermore, the experimental results indicated that yielding was easier under a tensile stress than under a compressive stress. The Kelvin probing method is promising and could be very suitable for determining yield onset of materials under complex loading conditions.

A new three-dimensional finite element method model of the conventional resistive thermal probe, usually employed within scanning thermal microscopy (SThM) has been developed. As a result, the line heat source characteristic of the bent thermal sensitive filament seems to permit the explanation of the experimental results within a certain frequency range. The verification of this line heat source characteristic of the thermal probe finally leads to the introduction of a general near-field condition of SThM, which considers the spatial and temporal characteristic of the heat source. Here, the contact area between the probe and the sample is not considered as the source but rather as the aperture between the heat source and the sample. In addition, the combination of this kind of thermal probe with the so-called 3ω-method has been justified for the quantitative determination of the local thermal conductivity. Moreover, the applicable sample thermal conductivity range has been expanded significantly by considering the varying heat flow into the sample within the conditional equation.

Please note that Shaohong Wang apologizes for omitting co-author Bradley Ferguson (The School of Electrical and Electronic Engineering, The University of Adelaide, SA 5005, Australia) and for failing to acknowledge his supporting partners.

This acknowledgment should have been added to the article:

This work was supported in part by the Center for Subsurface Sensing and Imaging Systems, under the Engineering Research Centers Program of the National Science Foundation (award number EEC-9986821) and Photonics Technology Access Program, Optoelectronics Industrial Development Association. The authors are very grateful to Mr Edward Walsby of University of Canterbury, New Zealand for providing silicon binary lenses. B Ferguson would also like to thank the US-Australian Fulbright program and the Australian Research Council.