Ferroelectric PTCR Films for Photonic Crystal Gas Sensor

Autor: J. Raviprakash, Irina Puscasu, Edward A. Johnson, Jing Gong Cheng, Ashak Shah, Anton C. Greenwald, Susan Trolier-McKinstry, Martin U. Pralle, Mark P. McNeal
Rok vydání: 2006
Předmět:
Zdroj: Scopus-Elsevier
ISSN: 1946-4274
0272-9172
DOI: 10.1557/proc-0952-f10-08
Popis: We examined lanthanum doped lead barium titanate films for temperature measurements of photonic crystal - MEMS devices. Films were deposited by sol-gel techniques and crystallized in air above 650°C. X-ray diffraction spectra consistent with the perovskite structure were detected. The room temperature dielectric constant was ∼570 at 10 kHz of La-doped (0.3 mol%) Pb0.3Ba0.7TiO3 films. These films had a remanent polarization of ∼20μC/cm2 and a coercive field of 145 kV/cm. The leakage current density was ∼ 2×10−7 amps/cm2 at 100 kV/cm field. The resistivity of the films extracted from the linear region of the I-V data (electric fields in excess of 100 kV/cm) measured as a function of temperature shows an increase in resistivity at temperatures above Tc (120°C for BaTiO3 and 240°C for Pb0.3Ba0.7TiO3) of the film consistent with positive coefficient of resistance (PTCR) effect. However, the change in resistance was small when compared to bulk samples of similar compositions.
Databáze: OpenAIRE
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