Showing papers in "European Physical Journal-applied Physics in 2010"

Magnetic imaging with spin-polarized low-energy electron microscopy

Abstract: Spin-polarized low-energy electron microscopy (SPLEEM) is a technique for imaging magnetic microstructures at surfaces and in thin films. In this article, principles, advantages and limitations of SPLEEM are reviewed. Several recent studies illustrate how SPLEEM can be used to investigate spin reorientation transition phenomena, to determine magnetic domain configurations in low-dimensional structures, or to explore physics of magnetic couplings in layered systems. The work highlights the capability of the technique to reveal in situ and in real time quantitative information on micromagnetic configurations and structure-property relationships. In addition, spectroscopic reflectivity measurements with spin-polarized low-energy electron beams can be a useful tool to probe spin-dependent unoccupied band structure of magnetic materials and electronic properties of buried magnetic interfaces.

Thermoelectric generator placed on the human body: system modeling and energy conversion improvements

Abstract: This paper focuses on the production of electricity using a thermoelectric generator placed on the human body connected to a dc-dc converter. The small difference in temperature between the hot heat source (e.g. the human body, T b = 37 °C) and the cold heat source (e.g. ambient air, T a = 22 °C), associated with a poor quality thermal coupling (mainly with the cold source), leads to a very low temperature gradient at the thermoelectric generator terminals and hence low productivity. Under these use conditions, the present article proposes an analysis of various ways to improve productivity given a surface capture system. Furthermore, we demonstrated, in this particular context, that maximizing the recovered electric power proves to be a different problem from that of maximizing efficiency, e.g. the figure of merit Z . We therefore define a new factor Z E , depending on the physical characteristics of thermoelectric materials, that maximizes electric power in the particular case where the thermal coupling is poor. Finally, this study highlights the benefit of sub-optimization of the power extracted from the thermoelectric generator to further improve efficiency of the overall system. We show that, given the conversion efficiency of the dc-dc converter, the maximum power point of the overall system is no more reached when the output voltage of the thermoelectric generator is equal to half of its electromotive force.

Shape-dependence of near-field heat transfer between a spheroidal nanoparticle and a flat surface

Abstract: We study the radiative heat transfer between a spheroidal metallic nanoparticle and a planar metallic sample for near- and far-field distances. In particular, we investigate the shape dependence of the heat transfer in the near-field regime. In comparison with spherical particles, the heat transfer typically varies by factors between 1/2 and 2 when the particle is deformed such that its volume is kept constant. These estimates help to quantify the deviation of the actual heat transfer recorded by a near-field scanning thermal microscope from the value provided by a dipole model which assumes a perfectly spherical sensor.

General modeling of the windings for multi-phase ac machines - Application for the analytical estimation of the mutual stator inductances for smooth air gap machines

Abstract: This paper, which deals with the winding modeling of ac multi-phase machines with a regular distribution of the stator slots, details an original matrix modeling of the stator winding. First, the properties of the balanced multi-phase windings (with integral-slot and fractional-slot patterns) are analysed. The winding function approach, one of the most common way to model the winding distribution effects on the stator rotating field, is then introduced. For multi-phase machines, it will be shown that the pole number generated by the winding distribution depends on a new parameter: the circularity index. The discrete nature of the winding, imposed by the stator slots, leads to the development of a discrete modeling of the winding obtained from sampling the winding function: two matrices, the winding function matrix and the distribution function matrix, are introduced to characterize the multi-phase winding. This matrix approach is thus a concise way to calculate the winding factors and to estimate the set of self and mutual stator inductances for smooth air gap multi-phase machines. A particularly original method of obtaining an analytical expression for the leakage mutual inductance is described. The results are validated with two experimental 5-phase PM machines by using experimental measurements and numerical simulations.

Structural and optical properties of iron (III) chloride tetraphenylporphyrin thin films

Abstract: Iron (III) chloride tetraphenylporphyrin (FeTPPCl) thin films are prepared on quartz and glass substrates at room temperature by thermal evaporation technique. The X-ray diffraction showed the amorphous nature for both the as-deposited and the annealed films at 423 K in air for 2 h, whereas the powder has the tetragonal form with lattice constants of a = 13.53 and c = 9.82 . The optical properties of FeTPPCl films are investigated using a spectrophotometric measurement of transmittance and reflectance at normal incidence of light in the wavelength range 190–2500 nm for the as-deposited and the annealed films. Absorption spectra of the films showed B, N and C absorption bands in the UV region followed by a Q-band in the visible region. The onset optical gap is determined from the analysis of the absorption coefficient values and found to be 1.53 eV for both the as-deposited and annealed films. The dispersion of the refractive index, n , is discussed in terms of Cauchy relation and the single oscillator model. The polarizability, the dispersion parameters, the ratio of free carrier concentration to the free carrier effective mass are also estimated.

Structural and optical properties of copper nitride thin films in a reactive Ar/N2 magnetron sputtering system

Abstract: Copper nitride films were prepared on glass and silicon substrates by reactive direct current magnetron sputtering at various N 2 -gas partial pressures at room temperature. The N 2 partial pressure influenced the structural, electrical and optical properties of the deposited films. The X-ray diffraction measurement showed the phase change of the preferred orientation of Cu 3 N planes of samples from Cu-rich (111) planes to N-rich (100) planes. The surface resistivity of glass substrate Cu 3 N films was between 1675 and 58 200 Ω/cm 2 and for silicon substrate films surface resistivity was between 13.2 and 2380 Ω/cm 2 . As is observed surface resistivity strongly affected by structures of the films. Deposition rate was influenced by the amount of argon gas since they are heavier than nitrogen atoms changes from 43 nm/min to 26 nm/min. Calculated band gap energy of the samples show a sharp enhancement from 1.4 eV to 1.95 eV by increasing nitrogen content in working gas.

A new simulation approach to characterizing the mechanical and electrical qualities of a connector contact

Abstract: Summary Due to ongoing miniaturization in electronics, connector contact designs have to follow the same trends. The prediction of the mechanical and electrical performance of low force connector contacts becomes increasingly important. This paper shows a new approach to model the elastic plastic contact of two multi-layered nonconforming rough bodies subjected to pressure and shear traction. Three main considerations will be presented. 1. To investigate the influence of the surface topography on contact performance, measured three dimensional digitized surfaces are not always available. Hence a numerical description of a ‘real’ rough surface is of great importance. It can be shown that an engineering surface can be modeled by five scale independent parameters: RMS roughness, x/y correlation length, kurtosis and skew. 2. Based on Papkovich Neuber Potentials and both multi grid and conjugate gradient methods, a numerical algorithm has been developed to calculate the stresses and deformations in a contact system with up to three different layers per contact partner. The plastic deformation of the individual contact points (a-spots) can be interpolated using different material hardening behaviors. 3. If the a-spot distribution is known, the constriction resistance of the true contact area can be calculated. The voltage drop inside the contacting bodies is interpolated by solving the Laplace equation iteratively. The different electrical properties of the contact layers as well as the interaction of the individual a-spots, is also taken into account. The simulation algorithms are validated using a Au/Ni/CuSn6 contact system. The results show excellent agreement between measured and simulated contact resistance results over a normal force range from 1 gram up to 250 grams. The algorithms are implemented with an ‘easy to use’ windows interface “First Contact”. The software also incorporates a material database that when used together with a surface modeler, allows for the fast calculation and 3d visualization of all mechanical and electrical contact characteristics..

Electronic structure of aluminum oxide: ab initio simulations of α and γ phases and comparison with experiment for amorphous films

Abstract: The electronic structure of γ-Al2O3 and α-Al2O3 has been investigated by means of the density functional theory. A comparison of the calculation results with experimental data for amorphous alumina films is also presented. The electronic structure is described in terms of band structure and density of states. It has been found that γ-Al2O3 have similar electronic structure with α-Al2O3 and amorphous Al2O3. Effective electron masses in γ-Al2O3 as well as in α-Al2O3 equal to ≈ 0.4 m 0 that is in a good agreement with the experimentally found tunnel electron mass in amorphous Al2O3. The heavy holes in both alumina crystals are explained by the valence band top forming by O 2p π nonbonding orbitals.

In situ diagnostic of etch plasmas for process control using quantum cascade laser absorption spectroscopy

Abstract: The combination of quantum cascade lasers and infra red absorption spectroscopy (QCLAS) opens up new possibilities for plasma process monitoring and control. First measurements are reported with an especially designed quantum cascade laser arrangement for application in semiconductor industrial environments to track the approach for in situ process control in silicon etch plasmas. In gas mixtures with N 2 and in microwave (MW) plasmas at pressures below 30 Pa concentrations of C 4 F 6 and of SiF 4 were measured simultaneously online for the first time. It could be demonstrated, that using quantum cascade lasers (QCL) it is possible to control ex situ mass flow controllers (MFC) based on in situ measured species concentrations in the gas phase and in the MW plasma bulk.

Electrical and gas sensing properties of polyaniline-chloroaluminium phthalocyanine composite thin films

Abstract: Electrical and gas sensing properties polyaniline-chloroaluminium phthalocyanine (PAni-CIAIPc) composite thin films were investigated to study the gas sensing behavior of composites. Devices (chemiresistor gas sensors) were prepared by spin coating method from PAni as the base of composites and CIAIPc (with different concentrations) as the second component onto interdigitated electrodes. The sensitivity, reversibility, response and recovery time of these thin films on exposure to different concentrations (0-2000 ppm) of CO 2 gas and the suitability of different composites as materials to be used in practical gas sensors at different temperatures were investigated. The sensitivity factor of composites was obtained in a range between 0.05-7.20. PAni + 10% CIAIPc was the perfect candidate composite to fabricate gas sensor at 300 K and PAni + 15% CIAIPc at 350 K. Thus, (PAni-CIAIPc) composites have better response than pure PAni. After that, devices were exposed to humidity, an unexpected behavior was absorbed. Conductivity of thin films were increased on exposure lower RH% and decreased on higher RH%. Finally, 1000 ppm CO 2 was mixed to humidity and introduced to chamber, obtained results showed the CO 2 mixtures decreased the sensitivity of thin films in compare with pure CO 2 .

Comparison of Pd/D co-deposition and DT neutron generated triple tracks observed in CR-39 detectors

Abstract: Solid state nuclear track detectors (SSNTDs), such as CR-39, have been used to detect energetic charged particles and neutrons. Of the neutron and charged particle interactions that can occur in CR-39, the one that is the most easily identifiable is the carbon breakup reaction. The observation of a triple track, which appears as three alpha particle tracks breaking away from a center point, is diagnostic of the 12 C(n, n’)3 α carbon breakup reaction. Such triple tracks have been observed in CR-39 detectors that have been used in Pd/D co-deposition experiments. In this communication, triple tracks in CR-39 detectors observed in Pd/D co-deposition experiments are compared with those generated upon exposure to a DT neutron source. It was found that both sets of tracks were indistinguishable. Both symmetric and asymmetric tracks were observed. Using linear energy transfer (LET) curves and track modeling, the energy of the neutron that created the triple track can be estimated.

Metamaterial absorber with random dendritic cells

Abstract: The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

Dusty plasmas: synthesis, structure and dynamics of a dust cloud in a plasma

Abstract: Plasmas are energetic media that can give birth to dust particles due to the presence of reactive gases or plasma-surface interactions. Industrial plasmas are often concerned by these dust particles that can be either unwanted or useful for the process. For fusion plasmas, production of dust particles from wall erosion is a serious issue for performance and safety reasons. In this article, some aspects of dusty plasmas with potential implications for plasma experimenters will be discussed. Convenient ways for detecting the presence or the growth of dust particles will be presented. The spatial distribution of the dust cloud during the plasma phase determines the subsequent dust particle deposition. It will be shown that some reactor regions can attract or repeal these dust particles. Finally, the dust particle dynamics after the plasma extinction will be investigated. A special attention will be paid on the residual electric charge that can stay attached on the dust particle surface and on its implications for dust particle control or deposition.

On physical properties of undoped and Al and In doped zinc oxide films deposited on PET substrates by reactive pulsed laser deposition

Abstract: Undoped and Al and In doped ZnO films were deposited on flexible PET substrates by Reactive Pulsed Laser Deposition (R-PLD). The morphological and structural characteristics of the obtained structures were investigated by AFM, SEM and XRD respectively. The transmittance spectra were recorded in the 300–1200 nm wavelength range and the electrical conductivity was measured. The samples appeared as granular and polycrystalline with high transparency and had a good electrical conductivity. The crystallinity of the undoped ZnO films improved with increasing pressure of the reactive oxygen gas. Doping of ZnO with Al or In modified the energy band gap and the resistivity of the material. The possibility for the application of such structures for the development of hybrid photovoltaic cells on flexible substrates will be demonstrated.

Black coatings: a review

Abstract: Black coatings are widely used in numerous applications e.g., decorative coatings, solar panels, optical instruments. The films are mostly prepared by liquid phase deposition or vapor phase deposition. In this paper we review the techniques of deposition and the properties of the most important black coatings. Optical properties are particularly presented and discussed.

Combustion synthesis of Dy3+, Eu3+ activated Na2X(PO4)F (X = Mg, Ca, Sr) phosphors for lamp industry

Abstract: In this paper we have reported synthesis and characterization of Dy 3+ and Eu 3+ activated Na2Mg(PO4)F, Na2Ca(PO4)F and Na2Sr(PO4)F phosphors. These phosphors were prepared by combus- tion synthesis and characterized by XRD and photoluminescence techniques. Dy 3+ ion gives PL emission in blue and yellow region of the visible spectrum by 385 nm excitation of the LED excitation and Eu 3+ ion gives PL emission in the red region of visible spectrum under 251 nm UV-excitation (Hg excitation), respectively. Therefore, above prepared Dy 3+ activated phosphors are more applicable for white LED and Eu 3+ activated phosphors are more applicable for Hg excitation lamp. Hence prepared, Dy 3+ and Eu 3+ activated Na2X(PO4)F (X = Ca, Sr, Mg) phosphors by combustion method are very potential application in the field of lamp industry.

Linear and nonlinear optical phenomena in nanostructured photonic crystals, filled by dielectrics or metals

Abstract: In this paper the results of linear and nonlinear optical properties investigations of globular photonic crystals, filled by dielectrics or metals, are presented.

Improving the contact resistance at low force using gold coated carbon nanotube surfaces

Abstract: Investigations to determine the electrical contact performance under repeated load cycles at low force conditions for carbonnanotube (CNT) coated surfaces were performed. The surfaces under investigation consisted of multi-walled CNT synthesized on a silicon substrate and coated with a gold film. These planar surfaces were mounted on the tip of a PZT cantilever and contacted with a hemispherical Au plated probe. The dynamic applied force used was 1mN. The contact resistance (Rc) of these surfaces was investigated with the applied force and with repeated loading cycles performed for stability testing. The surfaces were compared with a reference Au-Au contact under the same experimental conditions. This initial study shows the potential for the application of gold coated CNT surfaces as an interface in low force electrical contact applications.

Arc behavior in low-voltage arc chambers

Abstract: The arc behavior in an arrangement of parallel arc rails with a splitter plate in between has been investigated experimentally and in numerical computations. Thereby, the arc is simulated by coupling finite-volume modeling for the gasdynamics and finite-elements modeling for the electromagnetics. The formation of arc roots on the splitter plate can be described by a thin layer of elements with a current-density dependent specific resistance. The simulations were extended to model the experimental arrangement exactly. Additionally, net emission coefficients and radiation heat conductivity of air plasma instead of a simplified T 4 net emission of a black body were used to model the radiative cooling of the arc. The results of the arc voltage, the arc movement and the splitting process have been compared to measurements and high speed movies of the arc and yield good correlation. Moreover, the simulations allow good insight into the temperature distribution of the arc and the movement of the pressure waves caused at the arc ignition.

Analysis of positive corona in wire-to-plate electrostatic precipitator

Abstract: This paper analyses corona discharge in ambient air flow associated with laboratory-scaled wire-to-plate electrostatic precipitator (WPESP). The corona discharge is analysed by a combined iterative computational technique based on the finite element method (FEM) and charge simulation method (CSM). The phenomenon is mathematically described by Maxwell's equations in differential form. A finite element method is used to solve the Poisson's equation and the charge simulation method is used to satisfy the current continuity condition. Measurement method of the positive dc corona current density and electric field, taking into account the air flow velocity, has been introduced. The computed results are compared with experimental results to test the effectiveness of this approach.

Dielectric measurements in large frequency and temperature ranges of an aromatic polymer

Abstract: The characterization of the BPDA/PDA polyimide (PI) at high temperature up to 400 °C, thanks to dielectric relaxation spectroscopy (DRS) in the 10-1 Hz to 106 Hz frequency range, allows the determination of the dc electrical conductivity (σdc ). In such a high temperature range, the dielectric spectra are modified by the extrinsic electrode polarization phenomenon (EP) response. A model is proposed which coupled to the DRS results allows evidencing and quantifying the effect of the EP. The proposed method gives a simple way to determine the intrinsic σdc values from the effective ac dielectric response, improving the accuracy and reducing the duration of measurement. For BPDA/PDA PI, the resulting σdc values range from 4 × 10-11 to 8 × 10-6 Ω-1 m-1 for temperatures between 200 and 400 °C, with an activation energy of the conduction phenomenon of 0.55 eV.

Ultra high barrier materials for encapsulation of flexible organic electronics

Abstract: The encapsulation of the active layers (organic semiconductors, electrodes, transparent conductive oxides, etc.) of organic electronic devices developed onto flexible polymeric substrates is one of the most challenging issues in the rapidly emerging area of organic electronics. The importance for the protection of the active layers arises from the fact that these are very sensitive when they are subjected to the atmosphere, since the permeation of the atmosphere's water vapour (H 2 O) and oxygen (O gases induces corrosion effects, film delamination and finally, failure of the organic electronic device. In addition, the encapsulation layers contribute to the long-term stability of the whole device enabling its use in outdoor environments (e.g. in the case of flexible photovoltaic cells-OPVs). A promising approach for the encapsulation of flexible organic electronics includes the development of multilayers that consist of hybrid polymer materials and inorganic layers onto flexible polymeric substrates, such as poly(ethylene terephthalate) (PET). This approach leads to a significant improvement of the barrier performance of the whole structure, due to the synergetic effect of the confinement of the permeation to the defect zones of the inorganic layer, and the formation of chemical bonds between the hybrid polymer and the inorganic layer. The knowledge of their optical properties and their correlation with their barrier performance are of major importance since it will contribute towards the optimization of their functionality. In this work, we provide an overview on the results concerning the use of hybrid polymers as ultra high barrier materials and moreover we discuss on the effect of inclusion of SiO 2 nano-particles on their optical properties and barrier performance.

Hot-pressed Na+ ion conducting solid polymer electrolytes: (1 - x) PEO: x NaPO3

Abstract: Synthesis and ion transport property studies on hot-pressed Na + ion conducting solid polymer electrolytes (SPEs): (1- x ) PEO: x NaPO 3 , where x in wt.%, are reported. The compositional dependent conductivity ( σ ) studies revealed SPE film: (75PEO: 25NaPO 3 ) as the optimum conducting composition (OCC) with room temperature conductivity σ ~ 6.7 × 10 -7 S cm -1 , which is more than two orders of magnitude higher than that of pure PEO polymer host ( σ ~ 3.2 × 10 -9 S cm -1 ). Materials characterization and polymer-salt complexation were done with the help of XRD, FTIR, SEM, DSC techniques. In order to understand the ion transport behaviour in SPEs, the measurement on some basic ionic parameters viz. ionic conductivity ( σ ), ionic mobility ( μ ), mobile ion concentration ( n ), ionic transference number ( t ion ) have been carried out using different experimental techniques. The activation energy ( E a ) values involved in the thermally activated conductivity processes have been computed from “log σ - 1/ T ” Arrhenius plots.

Observation of antibacterial effects obtained at atmospheric and reduced pressures in afterglow conditions

Abstract: Bactericidal activities of three different afterglows operating at reduced and atmospheric pressures and ambient temperature are established and compared through the use of a unique protocol for bacteria (E. coli, CIP 54.8 T) exposition, recovery and numeration. The influence of three important parameters is shown. An original scenario for bacterial inactivation at reduced pressure is proposed, compatible with previously published results and with the observation of conformational changes appearing on the treated bacteria. © 2009 EDP Sciences.

Plasma nitriding of aluminium in a pulsed dc glow discharge of nitrogen

Abstract: Plasma nitriding of aluminium in a 50 Hz pulsed-dc glow discharge is studied for different ion-current densities (2.0-5.0 mA cm -2 ) by keeping the corresponding discharge parameters such as treatment time, chamber pressure, substrate temperature and gas composition same. The treated samples are analysed for changes induced in surface properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Vickers's micro-hardness testing. XRD showed the downshift in the original diffraction peak corresponding to (111) plane reflection along with the emergence of new diffraction peak corresponding to (220) plane reflection, confirming the N-diffusion into existing Al-lattice and formation of AlN compound. Surface hardness is significantly improved which might be attributed to the diffusion of nitrogen and compound layer formation.

Conductive nanocomposite ceramics as tribological and electrical contact materials

Abstract: Conductive ceramics have widespread use in many industrial applications. One important application for such materials is electrical contact technology. Over the last few years, a new class of nanocomposite ceramic thin film materials has been developed with contact coatings as one key objective. This family of materials has proven to combine the favorable contact properties of metals, such as low electrical and thermal resistivity, and high ductility, with those of ceramics such as low friction and wear rate, high chemical integrity and good high-temperature properties. Furthermore, it is also found that the tribological properties of such materials can be tailored by alloying thus creating a triboactive system. The technology is now industrialized, and a practical example of a contact system utilizing a nanocomposite coating for improved performance is given.

Characterization of 2-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile and ZnO nano-crystallite structure thin films for application in solar cells

Abstract: Hybrid (organic/inorganic) heterojunction device based on nano-crystallite structures of 2-(2, 3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile (DOPNA) and ZnO thin films has been fabricated. The ZnO powder is prepared by the hydrolysis of zinc chloride in the presence of triethanolamine, the ZnO film is prepared by using spin coating technique, whereas the DOPNA thin film is deposited from the powder by the thermal evaporation technique. The formed nano-crystallite structures and lattice parameters of DOPNA and ZnO films have been determined. The optical absorbance of DOPNA and ZnO films are measured and the types of transitions as well as the optical band gap of the films are evaluated. The current-voltage characteristics of ITO/ZnO/DOPNA/Au heterojunction diode in dark and under illumination conditions have been investigated. The capacitance-voltage characteristic showed that the formed junction is of abrupt nature and the built-in potential is estimated. The solar cell parameters have been determined as 0.37 V for open circuit voltage, 1.04 mA for short circuit current, 0.43 for fill factor and 1.56% for power conversion efficiency.

Quasi-solitons of the two-mode Korteweg-de Vries equation

Abstract: The two-mode Korteweg-de Vries equation (TMKdV) was proposed to describe the propagation of nonlinear waves of two different wave modes simultaneously. However, the existence of multi-soliton solutions is still unknown. In this letter we present two Hamiltonians, the conservation laws, and a Miura- like transformation of the equation. We show that the TMKdV equation has "quasi-soliton" behaviour in which waves moving in the same direction pass through each other almost without change of their wave forms except for phase shifts.

Helices of optimal shape for nonreflecting covering

Abstract: In this paper we study helical inclusions of a certain shape (called the “optimal shape”), such that the electric, magnetic, and magneto-electric polarizabilities are equal, and discuss unusual reflection properties of artificial materials based on such inclusions. We study helical particles with optimized design parameters, which can make the realization of media with equal dielectric and magnetic susceptibilities possible. Not canonical helix, which consists of a split loop with two straight-wire sections, but the true helix, which is obtained by bending a wire with a constant pitch angle is investigated. The geometry of the helices makes it possible to create a composite material with equal permittivity and permeability. In such material optimal helices are located in pairs and each pair consists of the right-handed and left-handed helix. Thus compensation of chiral properties of a material as a whole is achieved.

A Global Assessment Of Piezoelectric Actuated Micro-pumps

Abstract: This article provides an extensive outlook of different types of piezoelectric actuated micro-pumps published in the literature recently. We start by reminding the reader about the conventional operating parameters used to quantify the capabilities of these devices. After this introductory stage, we describe and classify the most prominent micro-pump's geometries found with piezoelectric actuation. At this point we identify the parameters given previously for each pump in order to establish a subsequent discussion in which the trends of different families are compared. Specific attention is given to the particularities of each case namely: flow rates and backpressures.