A. Cruz-Orea

Thermal Effusivity of the Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln=La, Eu) Ferroelectric Ceramic System by Inverse Photopyroelectric Technique

In this work, the thermal effusivities of Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln=La, Eu) ferroelectric ceramics are studied since it can be use as pyroelectric detectors. Photothermal techniques were used to determine thermal effusivity. The preparation of the ceramics was perform in our laboratory by using the oxide-mixing conventional method. It should be noticed that these ceramics were taken in an unpoled state. All measurements were made at room temperature.

Determination of Thermal Diffusivity and Thermal Effusivity of the (Bi0.5Na0.5)0.935Ba0.065TiO3 Ferroelectric Ceramics by Photothermal Techniques

In this work, the thermal diffusivity and thermal effusivity properties of the (Bi0.5Na0.5)0.935 Ba0.065TiO3 lead-free ferroelectric ceramics are studied since it can be use as pyroelectric detectors. Photoacoustic and photothermal techniques were used to determine thermal diffusivity and thermal effusivity respectively. The preparation of the ceramics was perform in our laboratory by using the oxide-mixing conventional method. The ceramics present high value of thermal diffusivity compared with barium Titanate. All measurements were made at room temperature.

Determination of Thermal Diffusivity of the Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln = La, Eu) Ferroelectric Ceramic System by Photoacoustic Technique

Thermal diffusivities of the Pb0.88(Ln)0.08Ti0.98Mn0.02O3 (Ln = La, Eu) ferroelectric ceramic system are investigated by using Open Photoacoustic Cell (OPC) technique. The preparation of the ceramics was performed in our laboratory by using the oxide-mixing conventional ceramic method. It should be noted that these ceramics were taken in an unpoled state. For the thermal characterization, measurements at room temperature, of the photoacoustic amplitude signals as a function of the light modulation frequency, were performed by using OPC technique. Experimental data were fitted to the OPC theoretical expression in the heat transmission configuration for optically opaque samples. The thermal diffusivity values obtained for these ceramics are close to those results reported for BaTiO 3 based ferroelectric ceramics.

Ceramic-Controlled Piezoelectric Bulk Implanted with Pt Wire Based on BaTiO3 (Optical Microscopy, SEM, EDS) and PLZT (Optical Bi-dimensional Characterization)

This paper describes the formation of poled bulk ferroelectric ceramics made of Lead Lanthanum Zirconate Titanate (PLZT) and Barium Titanate (BaTiO3). These ceramics were implanted during their fabrication with a platinum wire (Pt-wire), which worked as an internal electrode. This internal electrode was verified by means of optical microscopy, SEM, and EDS of the Barium Titanate (BaTiO3) ceramic to determine some chemical reaction. The analysis was checked only in BaTiO3 because it is the most common ferroelectric ceramic. Finally, the photovoltaic signal was measured in PLZT with the Pt-wire in a bi-dimensional experimental setup, with a resolution of 50 μm.

Photopyroelectric Microscopy Based on Pb0.88La0.08Ti0.98Mn0.02O3 Ferroelectric Ceramics

The use of photothermal microscopy to obtain superficial and in-depth images, by means of the interaction of a thermal wave with the analyzed material, has reached great interest due to its numerous applications. The application of the photopyroelectric microscopy technique with pyroelectric ceramic as a detector to avoid deformations due to the sample weight is presented in this article. Pyroelectric ceramic and linear micro-positioners were used to obtain the local photothermal signal of the sample. Then it is possible to get images of the studied sample through their differences in local thermal and optical properties.

Polivinilidene Fluoride (PVDF) applied to photopyroelectric microscopy

In this work we present the thermal images of biological and non-biological samples using photopyroelectric microscopy. The image of the thermal wave was obtained using a flexible film of polyvinylidene fluoride (PVDF) sensor in contact with the samples. Pyroelectric sensor was in the back-detection configuration in the case of biological sample. In the case of non-biological case the front-detection configuration was used. The signal obtained by the sensor was introduced into a lock-in amplifier and processed by a computer. In previous works thermal images of the non-biological samples has been obtained but in this work we obtained a good thermal image of biological material

Influence of poling voltage on optical absorption spectra, thermal properties, and structure of PLZT ceramics

ABSTRACT The evolution of the optical absorption spectra, thermal properties and structure of Pb1-xLax(ZryTi1-y)1-x/4O3 ferroelectric ceramics, which are widely known due to extended use in electronics, are studied when ceramics are submitted to different poling voltages. Structure analysis was done using XRD, Scanning Electronic Microscopy, and Rietveld Refinement. XRD and Rietveld Refinement attest phase transition upon poling. Thermal properties are investigated using Inverse photothermal technique. Thermal diffusivity results show an increment as poling voltage increase. Photoacoustic Spectroscopy is used to determine optical absorption spectra, revealing higher optical transmission through material when higher voltages are applied.