Enhanced electro-mechanical coupling of TiN/Ce0.8Gd0.2O1.9 thin film electrostrictor

Abstract

Gadolium doped ceria, Gd:CeO2 (CGO), have recently been shown to possess an exceptional high electrostriction coefficient (Q), which is at the least three orders of magnitude larger than the best performing lead-based electrostrictors, e.g. Pb(Mn1/3Nb2/3)O3. Herein, we show that CGO thin films fabricated by a pulsed laser deposition method can be directly integrated onto the Si substrate by using TiN films of few nanometers as functional electrodes. The exceptional good coupling between TiN and Ce0.8Gd0.2O1.9 yields a high electrostriction coefficient of Qe = 40 m4 C−2 and a superior electrochemomechanical stability with respect to the metal electrodes.

Electromechanical dopant–defect interaction in acceptor-doped ceria

“…[1][2][3] Furthermore, a recent discovery demonstrated that ceria thin films display an unconventional electromechanical strain at room temperature. [4][5][6][7] For example, the reported electrostriction coefficient (M e ) is around 6.5 Â 10 À18 (m V À1 ) 2 for [V O ] = 5%, i.e. 20 mol% Gd-doped ceria (GDC).…”

Electro-chemo-mechanical effect in Gd-doped ceria thin films with a controlled orientation

“…We evaluated the electromechanical performances by measuring the longitudinal M 11 and the transverse M 12 electrostriction coefficients. We used the cantilever vibration method 23 on the samples with in-plane top electrodes (Fig. S1 †).…”

“…2,7,[17][18][19][20][21] At room temperature, doped ceria showed outstanding electromechanical properties due to local distortion in the vicinity of oxygen vacancies. 22 Studies carried out on Gddoped ceria (CGO) thin lms, [22][23][24][25][26] bulk 27,28 and membranes, [29][30][31] show an average electrostriction coefficient of M e z 6 Â 10 À18 (m 2 V À2 ), 22 which is comparable to that of state-of-the-art materials such as Pb(Mn 1/3 Nb 2/3 )O 3 (M e ¼ 2 Â 10 À18 m 2 V À2 ). 32 For classical electrostrictors, Newnham et al provided a relationship in which the logarithm of performances depends on (S/3), where S is the elastic compliance and 3 is the dielectric constant.…”

“…The experimental setup and instruments are described elsewhere. 23 However, we added some new features described here. The interferometer resolution was 5 pm, but the background noise is usually higher, and it was not possible to observe displacements smaller than 3-4 nm.…”

“…M 13 has been measured in thin lms. 23,43 Here, we apply a top planar electrode conguration which allows investigation of the other electrostriction directions of the matrix i.e. M 11 and M 12 .…”