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A methodology is proposed to measure active electrical properties of polymeric materials focusing specifically ferroelectric response. The samples were obtained in the form of a film from polyvinylidene fluoride taking into account the control of the crystallinity. The specimens were mechanically oriented in an open roller mill at certain temperatures, being metallized in a high vacuum evaporator. The ferroelectricity tests were carried out at room temperature in a facility specially designed for that purpose, in the laboratories of the department of Applied Physics of the Higher Technical School of Telecommunications Engineering of Barcelona (ETSITB). The equipment used for ferroelectricity measurements, as well as the methods and procedures used, are suitable for teaching and research work related to the preparation and determination of active electrical properties in polymers, and can be applied to other types of ferroelectric materials. [ABSTRACT FROM AUTHOR]

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The progress made in recent decades in the development of sensors and actuators go hand in hand with advances in materials science, particularly with the ferroelectric materials. Those having large piezoelectric constants and large electromechanical coupling factors. Therefore, it is very important improve the production process and also to make investigations about appropriate physical properties of these materials for technological development. The piezoelectric properties of ferroelectric ceramics of lead zirconate titanate were investigated in room temperature, in the monoclinic phase [Pb(Zr0.52, Ti0.48)O3] and tetragonal phase [Pb(Zr0.50, Ti0.50)O3], and doped with different concentrations of iso-valent (SrO) and hetero-valent (Fe2O3) elements. A strong dependence of the piezoelectric properties with the symmetry and the relative concentration of dopants were observed. The results are discussed in terms of defect formation via doping, and the interaction of them with ferroelectric domains. [ABSTRACT FROM AUTHOR]

El artículo discurre sobre el análisis de la histéresis ferroeléctrica en capas delgadas. Los autores comentan sobre la importancia científica e industrial de las propiedades de materiales ferroeléctricos y describen el proceso de establecer los parámetros fundamentales del histéresis ferroeléctrica. También se examina el circuito Sawyer-Tower clásico.

The thin films of the composite (0.62)Ba0.90La0.067Zr0.09Ti0.91O3 (BLZT)-(0.38)CoFe2O4 (CFO) were grown on the electric conducting substrates of Nb-doped SrTiO3 (Nb: STO) by magnetron sputtering RF. The film crystalline structure was studied by X-ray diffraction showing that there are just BLZT and CFO phases in the film. In addition, we proposed a method in order to find the real P-E curves by substracting the Leakage density Current-Voltage from P-E curves, showing a decrease in the remanent polarization from 9.3 µC/cm² to 3.5 µC/cm², due to the presence of magnetic phase CFO. [ABSTRACT FROM AUTHOR]

The main characteristic of a material with ferroelectric properties is the hysteresis loop of its polarization. On the other hand, the information about the switching time is necessary in the application of the ferroelectric materials prepared as thin films in random access non volatile memories (NvFeRAM). On the other hand flexible systems to do ferroelectrics measurements can be implemented combining specific equipments controlled by a computer. In this work is described the upgrading of an installation to measure the hysteresis loops and the switching current transitory in thin films. The installation has been developed using the virtual instrumentation techniques, using conventional equipment of measurements coupled to a personal computer through a standard interface IEE488 and LabVIEW. [ABSTRACT FROM AUTHOR]

Magnetoelectric coefficient measurements on bulk samples of BiFeO3 (BFO) confirm the coupling between the magnetic and electrical polarization (the magnetoelectric effect). We prepared a target of BFO oxide for the solid-state reaction method. BFO thin films were grown on Pt/TiO2/SiO2/Si substrates at a working pressure of 4*10-1 mbar and temperatures between 400 and 600 °C by an rf magnetron sputtering technique. The structural and morphological properties of the films were studied by XRD and AFM respectively. Measures of ferroelectric hysteresis loops also were accomplished in order to confirm the ferroelectric character of the films. Studies of the magnetoelectric coefficient in thin film are under way with the aim of comparing with the material in bulk. [ABSTRACT FROM AUTHOR]

Ferroelectric properties and the chemical bonding states of lead zirconate titanate PbZr0.52Ti0.48O3 (PZT) thin films grown on SrRuO3/SrTiO3 by RF sputtering were investigated with X-ray photoelectron spectroscopy (XPS). The binding energy of the elements in the surface was investigated, as a chemical composition of the PZT ferroelectric thin films. By mean of a Radiant Technologies System to ferroelectric measurements were obtained hysteretic loops of P-E at room temperature, with values of 35.3 µC/cm², 64.5 µC/cm² and 171 4 kV/cm for remanent polarization, saturation polarization and coercitive field, respectively. A correlation was obtained between bonding states and PZT thin films ferroelectric properties [ABSTRACT FROM AUTHOR]

In the present work we report the magnetoelectric characterization of the new manganite Sr2TiMnO6 perovskite-like material. From measurements of magnetization as a function of temperature we determine the occurrence of a magnetic ordering for a critical temperature Tc=44.8 K and the existence of an irreversibility point at the magnetization measurements as a function of temperature for the Zero Field Cooling (ZFC) and Field Cooling (FC) regimes, became a strong evidence of frustration. Curves of magnetization as a function of applied field show a hysteretic behavior, characteristic of ferromagnetic materials. Curves of polarization as a function of applied voltage exhibit a ferroelectric response. Results reveal the occurrence of magnetoelectric response for the temperature regime T<44.8 K. [ABSTRACT FROM AUTHOR]

This paper describes the development of an installation to acquire the ferroelectric hysteresis loop of ceramic materials and to measure its characteristic parameters. The installation has been developed using the virtual instrumentation methods and is used in the characterization of ferroelectric materials developed by the Cuban groups of investigation in new materials and in laboratory practice of the matter Experimental Methods of the Physics. [ABSTRACT FROM AUTHOR]