Effects of defect dipoles on tunable dielectric response in relaxor ferroelectric ceramics

Abstract

Tunable dielectric materials have drawn much attention due to their wide applications including capacitors and microwave tunable devices. Ferroelectrics materials have special spontaneous polarization which can be reversibly switched by an external electric field. Therefore, tunable dielectric constant can be easily achieved in ferroelectrics. However, the study of nonlinear dielectric response induced by defect dipoles is rarely concerned. Here, we report the effects of defect dipoles on tunable dielectric response under alternative current (AC) and direct current (DC) electric field in defect dipoles introduced Pb(Lu1/2Nb1/2)O3–PbTiO3 ceramics. A modified Rayleigh model is proposed to successfully characterize dielectric nonlinearity and reveals the interaction between domain walls and defect dipoles. The defect dipoles had more sensitive effect on dielectric response under AC field than that of defect dipoles‐free samples. The drop of intrinsic dielectric contribution under AC field results from the detriment effect of defect dipoles. The irreversible contribution is altered by the movements of defect dipoles under AC field, subsequently inducing the nonlinearity of dielectric response. Samples with defect dipoles have larger tunable scope of dielectric properties than that of defect dipoles‐free samples. The present work discovers the potential of application of defect dipoles‐tuned dielectric response ferroelectrics in devices which requires both high AC and DC biases, and help to better understand the complex dielectric response of ferroelectrics.

Nonlinear Dielectric Response of Relaxor Ferroelectric (1 − x)Pb(Mg1/3Nb2/3)O3 − xPbTiO3 Epitaxial Thin Films

“…[ 46,57–59 ] In order to analyze the mechanism responsible for the thin film performance degradation, we quantitatively extract the extrinsic and intrinsic contributions via two different methods: 1) Rayleigh analysis under increasing ac excitation field and 2) frequency‐dependent permittivity measurements under increasing background dc bias. [ 5,21,39,47,60 ]…”

“…[ 23,37,38 ] The Rayleigh analysis is typically used to separate the intrinsic and extrinsic contributions and to describe the dielectric nonlinearity of ferroelectrics. [ 5,39 ] The Rayleigh law applied to the dielectric nonlinearity can be expressed as [ 5,25,39,40 ] $$$$\begin{equation}\varepsilon = {\varepsilon }_{{\rm{init}}} + \alpha {E}_{{\rm{ac}}}\end{equation}$$$$ $$$$\begin{equation}P\left( E \right) = {\varepsilon }_{\rm{o}}\left( {{\varepsilon }_{{\rm{init}}} + \alpha {E}_{{\rm{ac}}}} \right)E \pm \frac{\alpha }{2}{\varepsilon }_{\rm{o}}\left( {E_{{\rm{ac}}}^2 - {E}^2} \right)\end{equation}$$$$…”

“…[23,37,38] The Rayleigh analysis is typically used to separate the intrinsic and extrinsic contributions and to describe the dielectric nonlinearity of ferroelectrics. [5,39] The Rayleigh law applied to the dielectric nonlinearity can be expressed as [5,25,39,40] 𝜀 = 𝜀 init + 𝛼E ac ( 1)…”

Sb2O3‐modified lead zirconate titanate piezoelectric ceramics with enhancing piezoelectricity and low loss

“…First, the Q m of Sb 2 O 3 ‐doped ceramics might be increased because Sb ions entered the B‐site of the perovskite structure by acceptor doping, that is, Sb ions was in the center of the oxygen octahedron. It was surrounded by five oxygen ions, forming $${\rm{Sb}}_{\rm{B}}^{\rm{^{\prime}}} - V_{\rm{O}}^{\cdot \cdot}$$ defect dipoles 16–19 . The dipoles would tend to be oriented in the direction of spontaneous polarization, reducing the inversion activity of the electric domain.…”

“…It was surrounded by five oxygen ions, forming Sb ′ B − 𝑉 ⋅⋅ O defect dipoles. [16][17][18][19] The dipoles would tend to be oriented in the direction of spontaneous polarization, reducing the inversion activity of the electric domain. Thereby, the "pinning" effect of dipoles on domain walls made Q m increase.…”