Synthesis, Giant Dielectric, and Pyroelectric Response of [001]-Oriented Pr3+ Doped Pb(Mg1/3Nb2/3)O₃-PbTiO₃ Ferroelectric Nano-Films Grown on Si Substrates.

Changlong Cai,Yongming Su,Shun Zhou,Xueping Sun,Deqiang Zhang,Jun Wang,Dabin Lin,Weiguo Liu

doi:10.3390/ma11122392

Changlong Cai, Yongming Su + Show 6 more

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https://doi.org/10.3390/ma11122392

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Abstract

The [001]-oriented Pr3+ doped Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (Pr-PMN-PT) thin films with a composition near the morphotropic phase boundary (MPB) were synthesized by a sol–gel method. The crystal structure was characterized using X-ray diffraction. It was found that a single perovskite phase was achieved in Pr-PMN-PT thin films annealed at 650 °C for 3 min. The dielectric constant (εr) value was 2400 in 2.5% Pr-PMN-PT thin films at room temperature, 110% higher than that of pure PMN-PT samples. Through 2.5% Pr3+ doping, remanent polarization (Pr) and coercive field (Ec) values increased from 11.5 μC/cm2 and 35 kV/cm to 17.3 μC/cm2 and 63.5 kV/cm, respectively, in PMN-PT thin films. The leakage current densities of pure and 2.5% Pr-PMN-PT thin films were on the order of 1.24 × 10−4 A/cm2 and 5.8 × 10−5 A/cm2, respectively, at 100 kV/cm. A high pyroelectric coefficient (py) with a value of 167 μC/m2K was obtained in 2.5% Pr-PMN-PT thin films on Si substrate, which makes this material suitable for application in infrared detectors.

Highlights

IntroductionPb(Mg1/3 Nb2/3 )O3 -PbTiO3 (PMN-PT) bulk piezoelectric materials with compositions near the morphotropic phase boundary have attracted much attention as a candidate piezoelectric material for device application in the fields of microelectromechanical system (MEMS) and nanoelectromechanical systems (NEMS) [1,2,3]—such as infrared (IR) detectors [4], cantilever-type piezoelectric devices [5,6], multilayer capacitors [7], and ultrasonic transducers [8,9,10]—due to the high field strain (1.7%) [11], pyroelectric coefficient (~1500 μC/m2 K) [12], and longitudinal coupling factor (~95%) [13,14]
Avoiding the formation of a pyrochlore phase is a key factor for the synthesis of Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 (PMN-PT) thin films as the addition of this phase will reduce the piezoelectric and ferroelectric properties of the resulting thin films
Compared to the typical PMN-PT solid solution, the single perovskite structure was obtained at 650 ◦ C, which showed two strong peaks at 2θ = 22.2◦

Summary

Introduction

Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 (PMN-PT) bulk piezoelectric materials with compositions near the morphotropic phase boundary have attracted much attention as a candidate piezoelectric material for device application in the fields of microelectromechanical system (MEMS) and nanoelectromechanical systems (NEMS) [1,2,3]—such as infrared (IR) detectors [4], cantilever-type piezoelectric devices [5,6], multilayer capacitors [7], and ultrasonic transducers [8,9,10]—due to the high field strain (1.7%) [11], pyroelectric coefficient (~1500 μC/m2 K) [12], and longitudinal coupling factor (~95%) [13,14]. For PMN-based bulk crystals, the pure perovskite structure can be synthesized using the two-step columbite precursor method [15,16,17]. The second pyrochlore phase in PMN-PT thin films is related to many factors, for example annealing temperature/time [18], sample thickness [19], excess Pb content [20,21], etc., which restrict the pyroelectric, piezoelectric, and dielectric properties in PMN-PT thin films.

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