resumo
Electromechanical response of 1.5 mu m thick 2 mm diameter self-supported films (membranes) of 20 mol% Gddoped ceria with Ti electrodes was measured at two temperatures (25 and 75 degrees C) as a function of direct (U00 and alternating (U-Ac, 20 Hz) voltages. The films assumed a soup-panbowl shape and application of the external voltage resulted in a uniform vertical shift of the flat area. In the absence of superimposed U-DC, Upc induces electromechanical response at the 1st and 2nd harmonics at both temperatures. The amplitude of the 2nd harmonic is proportional to U-Ac(2) at these temperatures and it is independent of U-DC, which identifies it as due to the electrostriction effect. Direct measurement of the built-in bias via minimization of the 1st harmonic response, as well as electrical impedance and I-V measurements indicate that, although asymmetry of the contacts may contribute to the appearance of the 1st harmonic, it is insufficient to explain it. Based on the fact that the force displacement curve of the membrane measured with AFIVI is hysteretic, we hypothesize that the 1st harmonic response is related to the non-linear mechanical deformation of the buckled film.
palavras-chave
ELECTROSTRICTION; TEMPERATURE
categoria
Chemistry; Physics
autores
Mishuk, E; Ushakov, AD; Cohen, SR; Shur, VY; Kholkin, AL; Lubomirsky, I
nossos autores
Andrei Kholkin
Investigador Jubiladoagradecimentos
This work was supported by the Israeli Ministry of Science and Technology within the program of Israel-Russian Federation Scientific Collaboration, grant #12421-3. This research is made possible in part by the historic generosity of the Harold Perlman Family. The equipment of the Ural Center for Shared Use "Modern Nanotechnology" of Ural Federal University was used. The research was made possible in part by RFBR (grant 15-52-06006 MNTI_a). This work has been supported in part by the Ministry of Education and Science of the Russian Federation under projects nos. 3.9534.2017/BP and 3.4993.2017/6.7 and Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). A.L.K. acknowledges the support of CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013) financed by national funds through the FCT/MEC and, when applicable, co-financed by FEDER under the PT2020 Partnership Agreement.