Sidney Lang

Ben-Gurion University of the Negev | bgu

Direct current electrical poling of textured hydroxyapatite (HAp) ceramics is reported here to exhibit weak ferroelectricity and pyroelectricity, but a remarkably higher (six orders of magnitude) piezoelectricity. The piezoelectric strain coefficient is an order higher than that of bone and of the same order as that of quartz crystal and uncalcifie...

Hydroxyapatite nanocrystals in natural form are a major component of bone- a known piezoelectric material. Synthetic hydroxyapatite is widely used in bone grafts and prosthetic pyroelectric coatings as it binds strongly with natural bone. Nanocrystalline synthetic hydroxyapatite films have recently been found to exhibit strong piezoelectricity and...

Enhanced piezoelectricity and nature of electric-field induced structural phase transformation in textured lead-free piezoelectric Na0.5Bi0.5TiO3-BaTiO3 ceramics Appl. Phys. Lett. 100, 172906 (2012) Effect of doping on polarization profiles and switching in semiconducting ferroelectric thin films J. Appl. Phys. 111, 084105 (2012) Scaling behavior o...

Micro-domains of modified surface potential (SP) were created on hydroxyapatite films by direct patterning by mid-energy focused electron beam, typically available as a microprobe of Scanning Electron Microscopes. The SP distribution of these patterns has been studied on sub-micrometer scale by the Kelvin Probe Force Microscopy method as well as ly...

This work reports on a novel advanced method of studying proteins in solutions. Superior sensitivity can be achieved by treating the surface of the quartz crystals in such a way as to attract or repel materials based upon their electrical charge. Protein solutions are especially interesting because the net charge of the protein molecule can be chan...

Hydroxyapatite (HA) is the major component of bone and is used in artificial form in many biomedical applications. It was once believed to have a centrosymmetric crystal structure. In theoretical and experimental studies published in 2005, it was shown to have a monoclinic P21 structure. In the work reported here, 500 nm films of HA were spin-coate...

Nano-sized BaSrTiO₃ particles and a dispersant were incorporated in samples of low density polyethylene (LDPE). The nanoparticle loading was 2% or 10% by weight, and the dispersant loading was 4 parts per hundred relative to BaSrTiO₃. dc conductivity measurements were made in the temperature range 30-70°C in vacuum, and in air...

The recently developed Laser Intensity Modulation Method (LIMM) has proven to be a very useful technique for determining the thickness spatial distribution of polarization or space charge in ferroelectric materials. A major drawback in the analysis of LIMM measurements is the necessity of solving a Fredholm integral equation of the 1st kind using e...

Abstract Micro-domains of modified surface potential (SP) were created on hydroxyapatite films by direct patterning by mid-energy focused electron beam, typically available as a microprobe of Scanning Electron Microscopes. The SP distribution of these patterns has been studied on sub-micrometer scale by the Kelvin Probe Force Microscopy method as w...

The introduction of porosity into ferroelectric ceramics has been of great interest in recent years. In particular, studies of porous lead-zirconate-titanate ceramic (PZT) have been made. In the research reported, samples of Ferroperm Pz27 with porosities of 20, 25 and 30% were studied. Very complete measurements were made of all of the physical pr...

The Laser Intensity Modulation Method (LIMM) is widely used for the determination of the spatial distribution of polarization in polar ceramics and polymers, and space charge in non-polar polymers. The analysis of experimental data requires a solution of a Fredholm integral equation of the 1st kind. This is an ill-posed problem that has multiple an...

A new, non-destructive technique for the analysis of electret materials is presented. Thermal-pulse tomography produces three-dimensional images of space-charge and polarization distributions with a lateral resolution of better than 50μm and a depth resolution of less than 0.5μm. A focused-pulsed laser heats a circular spot on the opaque upper elec...

The Laser Intensity Modulation Method (LIMM) is a technique for the determination of polarization and/or space charge profiles in the thickness direction of ceramic and polymeric samples. The experimental data are analyzed by means of a Fredholm integral equation of the first kind. This equation admits to multiple and very different solutions. A nu...

DC conductivity and AC impedance measurements were made in vacuum on samples of low density polyethylene to which nano-sized BaSrTiO₃ particles (60/40 barium/strontium ratio) and a dispersant had been added. The samples were 150-200 mum thick. The temperature range was 30-70degC. The vacuum dc conductivity in samples containing the dispe...

A recently-developed addition to the methods is the Monte Carlo technique (MC). In MC, the LIMM integral equation is written as a summation over a number of spatial positions. These are selected randomly and the electric field is calculated at each of these points using least-squares. This process is repeated a very large number of times and the re...

Sol–gel techniques were used to prepare thin films of Pb(Zrx ,Ti1−x )O3 (PZT) with three different Zr/Ti ratios and a graded PZT film with three different compositional layers. A Michelson interferometer was used to measure the thickness strains due to an applied ac electric field. Effective d 33 piezoelectric strain coefficients were computed from...

The 25 papers in this special issue focus on the applications of ferroelectrics.

DC conductivity and ac impedance measurements were made in air and in vacuum on samples of low density polyethylene to which nano-sized and micro-sized ZnO particles and a dispersant had been added. The samples were 150-200 mum thick. The temperature range was 30-70degC. The temperature dependence of the vacuum dc conductivity in samples containing...

The 39 papers in Part I of this special issue focus on the applications of ferroelectrics. The issue seeks to address the current state of the field by providing an overview of the fundamental materials science required to advance the discipline, as well as detailed papers on the applications of ferroelectric materials.

A modification of a technique for the measurement of the thermal diffusivity of thin solid materials is presented. The technique is called Thermal Diffusivity by Laser Intensity Modulation Method (LIMM-TD). It is based on the measurement of the phase retardation of a thermal wave passing through the test material by means of a lead-zirconate-titana...

This paper discusses the mechanisms that can contribute to the enhanced longitudinal piezoelectric effect along nonpolar directions in perovskite crystals, such as BaTiO3, PbTiO3, KNbO3, Pb(Mg1/3Nb2/3)O-3-PbTiO3 and Pb(Zn1/2Nb2/3)O-3-PbTiO3. Piezoelectric anisotropy is discussed in relation to temperature induced phase transitions, compositional va...

Three kinds of near-field microscopy imaging mode including SEAM (Scanning electron acoustic microscopy), PFM (Piezoresponse force microscopy) and SPAM (Scanning probe acoustic microscopy) have been developed to investigate domain structures of ferroelectric ceramics, crystals and thin films in our studies. The domain imaging mechanisms are present...

The last two decades have witnessed the proliferation piezoelectric composite transducers for an array of sensor and actuator applications. In this article, a concise summary of the major methods used in composite making, with special emphasis on Solid Freeform Fabrication (SFF), is provided. Fused Deposition of Ceramics (FDC) and Sanders Prototypi...

Dielectric response of vinylidene fluoride type ferroelectric polymers is dominated by that of segmental motions in the amorphous phase in temperature range 200–300 K and contributions related to the local mode and ferroelectric-paraelectric transition in the crystalline phase of the polymer at higher temperatures. Diffuse and frequency-dependent d...

The central problem in the physics of relaxors is the nature of the polar nanoclusters. Whereas relaxors are homogeneous at high enough temperatures, polar nanoregions immersed in a neutral matrix are formed below a certain temperature Tb. This should lead to a two component system. Here we present direct microscopic evidence for the two component...

The magnetoelectric (ME) effect of piezoelectric-magnetostrictive laminate composites, which is a product tensor, has been studied. Based on piezoelectric and piezomagnetic constituent equations, the longitudinal-mode vibration and equivalent circuits have been derived. The effective magnetoelectric coupling coefficient, voltage-gain, and output ef...

The goal of this research was the development of a portable therapeutic device for the treatment of diabetes. A 3×3 cymbal array has been successfully tested in noninvasive insulin delivery experiments. The cymbal is a composite flextensional transducer constructed from a poled PZT ceramic and shaped metal endcaps that amplify the transducer motion...

Composites of triglycine sulfate (TGS) powder dispersed in a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE), 70/30 mol%) copolymer matrix have been prepared using solvent casting followed by compression moulding. The composites have been characterized by means of scanning electron microscopy (SEM) and differential scanning calorimetry (DS...

Relaxor ferroelectrics were discovered almost 50 years ago among the complex oxides with perovskite structure. In recent years this field of research has experienced a revival of interest. In this paper we review the progress achieved. We consider the crystal structure including quenched compositional disorder and polar nanoregions (PNR), the phase...

Heat generation is one of the significant problems in piezoelectrics for high power density applications. In this paper, we review the loss mechanisms in piezoelectrics first, followed by the heat generation processes for various drive conditions. Heat generation at off-resonance is caused mainly by dielectric loss tan δ′ (i.e., P-E hysteresis loss...

A bibliography is given containing 1683 references published during 2005 on piezoelectric and pyroelectric properties of materials and their applications. It contains listings of journal articles, patents and dissertations with complete bibliographic citations. References in which the first author's name begins with letters between N and Z are give...

Dc conductivity and ac impedance measurements were made in air and in vacuum on samples of low density polyethylene to which nano-sized and micro-sized ZnO particles and a dispersant had been added. The samples were 150-200 mum thick. The temperature range was 30-70degC. The temperature dependence of the vacuum dc conductivity in samples containing...

A modification of a technique for the measurement of the thermal diffusivity of thin solid materials is presented. It is based on the measurement of the phase retardation of a thermal wave passing through the test material by means of a PZT pyroelectric detector. It is not necessary to know either the pyroelectric coefficient of the detector or the...

The field of ferroelectricity is a very active one. Many hundreds of papers in this field are published each year and a large number of local and international conferences are held. The material in this book originally appeared in the Journal of Materials Science. The special issue entitled Frontiers of Ferroelectricity appeared as Volume 41, Issue...

The piezoelectric effect was first observed in polyvinylidene fluoride polymer (PVDF) in 1969, and the pyroelectric effect was found several years later. A number of additional ferroelectric polymers have been discovered since that time including the copolymer PVDF with trifluoroethylene (P(VDF-TrFE)), and the odd-numbered nylons. A large number of...

Electric field/space charge profiles obtained using the laser-intensity-modulation-method (LIMM) are presented for XLPE samples machined from power cable insulation cross-linked using dicumyl peroxide. The samples, 110 mum thick with vacuum-evaporated aluminium electrodes, were subjected to DC fields of 48 kV/mm and both polarities at room temperat...

Electric field and space charge profiles were measured in 110 mum thick planar XLPE samples machined from the insulation of power transmission cables. The samples carried vacuum-evaporated aluminium electrodes, and were poled at field-strengths around 50 kV/mm (both polarities) for periods up to 48 hr. The electric field and space charge profiles w...

In this short paper, the Kramers-Kronig relations for the laser intensity modulation method (LIMM) are presented to check the self-consistency of experimentally obtained complex current densities. The numerical procedure yields well defined, precise estimates for the real and the imaginary parts of the LIMM current density calculated from its imagi...

A bibliography is given containing 1887 references published during 2004 on piezoelectric and pyroelectric properties of materials and their applications. It contains listings of journal articles and patents with complete bibliographic citations. Journal and patent references from 2004 in which the first author's name began with letters between A a...

The Laser Intensity Modulation Method (LIMM) is widely used for the determination of the spatial distribution of polarization in polar ceramics and polymers, and space charge in non-polar polymers. The analysis of experimental data requires a solution of a Fredholm integral equation of the 1st kind. This is an ill-posed problem that has multiple an...

A worldwide effort is underway to remove lead from many commercial products. Most ferroelectric ceramics contain lead, principally those based on lead-zirconate-titanate solid solutions. Recently a new non-lead containing composition series has been developed by Saito et al. These are alkaline niobate based materials with the composition (K 0.5 Na...

Three-dimensional imaging of space-charge and polarization distributions in electret materials has been imple- mented by means of laser-induced thermal pulses. In pyroelectric films of poled poly(vinylidene fluoride), images of 45◊45 pixels with a depth-resolution of less than 0.5 µm and a lateral resolution of 40 µm were recorded, the latter being...

Three-dimensional polarization and space-charge mapping with focused thermal pulses was performed on various electret polymers. In polyvinylidene fluoride (PVDF) films with a structured polarization, a lateral resolution of 38 μm and a near-surface depth resolution of better than 0.5 μm was achieved. In piezoelectric sensor cables, this technique m...

A package of programs written using the symbolic mathematics program, Mathematica®, has been developed. Its principal usage is in teaching the LIMM method to students and demonstrating data analysis by means of the Polynomial Regularization Method (PRM). A large number of variables can be changed in the program and their effects can be shown graphi...

A bibliography is given containing 1911 references published during 2003 on piezoelectric and pyroelectric properties of materials and their applications. It contains listings of journal articles and patents with complete bibliographic citations. This bibliography is the continuation of a series published semi-annually.

Scientists are using advanced infrared radiation (IR) imaging tools for treatment of pyroelectricity in terms of a change in net dipole moment emerged in moder times. Detector elements made of lead strontium titanate (PST) or barium strontium titanate (BST) are commonly used. The devices operate at room temperatures above the Curie level and an app...

The Fredholm integral equation of the laser intensity modulation method is an ill-conditioned problem with multiple solutions. An approach based on an application of the Monte Carlo technique and a least-squares solver is developed and tested on simulated data containing both Gaussian and white noise. Good agreement between the original polarizatio...

International Conference of German physical Society held in March 2005

High-resolution, large-area three-dimensional mapping of polarization profiles in electret polymers was carried out by means of a fast thermal pulse technique with a focused laser beam. A lateral resolution of 38 mum and a near-surface depth resolution of less than 0.5 mum was achieved. At larger depths, fast thermal diffusion in the metal electrod...

The piezoelectric effect was first observed in polyvinylidene fluoride polymer (PVDF) in 1969 and the pyroelectric effect was found several years later. A number of additional ferroelectric polymers have been discovered since that time including the copolymer PVDF with trifluoroethylene (P(VDF-TrFE)), and the odd-numbered nylons. A large number of...

The determination of the polarization distribution by means of the laser intensity modulation method (LIMM) requires a solution of a Fredholm integral equation of the 1st kind. This is an ill-conditioned problem that can lead to multiple and very different solutions. One of the more frequently used solution methods is based upon Tikhonov regulariza...

We present, for XLPE samples cross-linked by the silane process, polarization/space charge profiles obtained using the laser-intensity-modulation-method (LIMM), with an estimated spatial resolution of 2 μm. The samples, 100 μm thick with vacuum-evaporated aluminium electrodes, were subjected to dc fields of 50 kV/mm at room temperature for 18 hr. T...

A new form of biomineralization in the pineal gland of the human brain has been studied. It consists of small crystals that are less than 20 μm in length and that are completely distinct from the often-observed mulberry-type hydroxyapatite concretions. Cubic, hexagonal and cylindrical morphologies have been identified using scanning electron micros...

Pyroelectricity was probably first observed by the Greeks more than 24 centuries ago. The philosopher Theophrastus wrote that lyngourion (most likely the mineral tourmaline) had the property of attracting straws and bits of wood. For two millennia the peculiar properties of tourmaline were more a part of mythology than of science. In the eighteenth...

Physical properties of a bimorph and two trimorph multilayer BaTiO3 ceramic compositions with a gradient in Sn content were studied. The measurements made included polarization and strain hysteresis, dielectric permittivity, thermal diffusivity and polarization distributions by means of the Laser Intensity, Modulation Method (LIMM).

A bibliography is given containing 2399 references published during 2001 and 2002 on piezoelectric and pyroelectric properties of materials and their applications. It includes journal articles, patents and doctoral dissertations with complete bibliographic citations. This bibliography is the continuation of a series published semi-annually.

A bibliography is given containing 2039 references published during 1999 and 2000 on piezoelectric and pyroelectric properties of materials and their applications. It includes journal articles, patents and doctoral dissertations with complete bibliographic citations. This bibliography is the continuation of a series published semi-annually.

The surface laser intensity modulation method (SLIMM) is used for the determination of the spatial distribution of the polarization normal to and near the surface of a ferroelectric sample. The experimental data measured are pyroelectric currents as functions of frequency. The data analysis requires the solution of a Fredholm integral equation of t...

A technique for the measurement of the thermal diffusivity of thin samples of solid materials is presented. It is based on the measurement of the phase retardation of a thermal wave passing through the test material. The test material, which can be either ferroelectric or non-ferroelectric, is attached by means of a high thermal conductivity cement...

A bibliography is given containing 1224 references published during 1999 and 2000 on piezoelectric and pyroelectric properties of materials and their applications. It includes journal articles and some conference proceedings. Complete bibliographic citations and additional information such as language and original sources of translations are given....

A new form of biomineralization has been studied in the pineal gland of the human brain. It consists of small crystals that are less than 20 microm in length and that are completely distinct from the often observed mulberry-type hydroxyapatite concretions. A special procedure was developed for isolation of the crystals from the organic matter in th...

The pineal gland is a neuroendocrine transducer secreting melatonin, responsible for the physiological circadian rhythm control. A new form of biomineralization has been studied in the human pineal gland. It consists of small crystals that are less than 20 µm in length. These crystals could be responsible for an electromechanical biological transdu...

A new form of biomineralization has been found in the pineal gland of the human brain. The crystals are 10 to 20 w m in length and have well-defined morphologies. Several structure types have been identified using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) showed that the crystals contain only the elements calcium, car...

Transparent glass nanocomposites in the pseudo binary system (100−x) SrB4O7 (SBO)–x Bi2VO5.5 (BiV) (0≤x≤70) were prepared by the splat quenching technique. The nano-crystallization of bismuth vanadate (BiV) in 50 SBO–50 BiV (in mol%) glass composite has been demonstrated. These were characterized for their structural, thermal and dielectric propert...

The Laser Intensity Modulation Method (LIMM) has recently been extended to the study of thin-film ferroelectrics on a substrate. The analysis of the experimental data requires the numerical solution of a Fredholm integral equation of the 1st kind, an ill-posed problem having multiple solutions. The techniques that have been applied previously for t...

A thermal analysis is a critical part of the design of thin-film pyroelectric infrared detectors. Because of the high thermal conductivity of the silicon substrate, it is necessary to isolate the pyroelectric layer thermally. The isolation is accomplished by either use of a low thermal conductivity insulating layer or a bridge structure. If the hea...

The Laser Intensity Modulation Method (LIMM) has recently been extended to the study of thin-film ferroelectrics on a substrate. The analysis of the experimental data requires the numerical solution of a Fredholm integral equation of the 1st kind, an ill-posed problem having multiple solutions. The techniques that have been applied previously for t...

A bibliography of 1212 references on piezoelectric and pyroelectric properties of materials and their applications published during 1997 is given. It includes journal articles, published conference proceedings, books, chapters in books, patents, doctoral theses and reports. Complete bibliographic citations and additional information such as languag...

Many thousands of papers have been published on the piezoelectric, pyroelectric and ferroelectric properties of single crystals, ceramics, polymers and liquid crystals. Yet fewer than 100 papers have appeared on these properties in biological materials. Piezoelectric and pyroelectric effects have been measured on a number of plant and animal tissue...

A bibliography of 884 references on piezoelectric and pyroelectric properties of materials and their applications published during 1996 and 1997 is given. It includes journal articles, published conference proceedings, books, chapters in books, patents, doctoral theses and reports. Complete bibliographic citations and additional information such as...

Determination of the polarization distribution in ferroelectrics using LIMM requires the solution of a Fredholm integral equation of the 1st kind. The constrained regularization method which has been used successfully to solve this problem for single-layer ferroelectrics fails when applied to thin films on a multi-layer substrate. A new approach ba...

The Laser Intensity Modulation Method (LIMM) is used to determine the spatial distribution of polarization in the direction of the polar axis of a ferroelectric sample. It is based upon measurement of the pyroelectric current generated by the material when it is heated with a laser beam which is intensity-modulated over a range of frequencies. A mo...

Pyroelectricity was probably first observed by the Greeks more than 23 centuries ago. The philosopher Theophrastus wrote that lyngourion, probably the mineral tourmaline, had the property of attracting straws and bits of wood. For 2000 years, the peculiar properties of tourmaline were more a part of mythology than of science. In the 18th Century, p...

A bibliography of 1807 references on piezoelectric and pyroelectric properties of materials and their applications published during 1996 and 1997 is given. It includes journal articles, published conference proceedings, books, chapters in books, patents, doctoral theses and reports. Complete bibliographic citations and additional information such a...

The SLIMM (surface laser intensity modulation method) is used for the determination of polarization distributions near the surfaces of ferroelectric samples. The experimental data measured are pyroelectric currents as functions of frequency. The data analysis requires the solution of a Fredholm integral equation of the 1st kind. This is an ill-pose...

A bibliography of 692 references on piezoelectric and pyroelectric properties of materials and their applications published during 1995 is given. It includes journal articles, published conference proceedings, books, chapters in books, patents, doctoral theses and reports. Complete bibliographic citations and keywords are presented in a References...

Triglycine sulfate-gelatin (TGS-gelatin) films were grown by evaporation of the water from a solution containing gelatin and TGS. The pyroelectric and dielectric properties of the films were highly dependent on their water content. Moist films had higher pyroelectric coefficients and lower coercive fields than dry films. The dielectric permittivity...

The Laser Intensity Modulation Method (LIMM) is based on the measurement of the pyroelectric current generated by the material when it is heated with a laser beam which is intensity-modulated over a range of frequencies. A modification of this technique was developed which permits detailed profiling of the polarization distributions in a layer adja...

A bibliography of 899 references on piezoelectric and pyroelectric properties of materials and their applications published during the period 1992-1994 is given. It includes journal articles, published conference proceedings, books, chapters in books, patents, doctoral theses and reports. Complete bibliographic citations and keywords are presented...

Melatonin secretion by the pineal gland has been reported to be affected by exposure to electromagnetic fields (EMFs). In an initial investigation to determine if calcifications commonly found in the pineal gland could respond to EMFs by a transducer mechanism, studies were conducted to ascertain if pineal tissues were piezoelectric. Second harmoni...

Pyroelectricity is the electrical response of a material to a change in temperature. It exists in polymers which contain spontaneous or frozen polarization resulting from oriented dipoles. This review describes the physical basis for the existence of the pyroelectric effect and discusses its behavior in a number of amorphous, semicrystalline, cryst...