The ferroelectric compound family Pb(Zr x Ti1−x )O3 (PZT) is one of the most investigated and widely used piezoelectric materials. Optimization of the piezoelectric coefficients is observed for x ~ 0.52 (Pb(Zr0.52Ti0.48)O3) and is further promoted by the increase of grain size (GS). However, in some cases the piezoelectric properties of Pb(Zr0.52Ti0.48)O3 deteriorate upon processing due to the decrease of density, ρ, that is mostly ascribed to the appearance of byproduct phases. In the present study we discuss the influence of the processing conditions on the piezoelectric properties for polycrystalline Pb(Zr0.52Ti0.48)O3, specifically focusing on the sintering temperature, 1100 °C ⩽ T sin ⩽ 1250 °C. To this end, we use atomic force microscopy (AFM), Archimedes’ method, x-ray diffraction (XRD) and a newly introduced local technique, based on a conventional optical microscope, which is further developed here to accommodate non-clamped specimens. The data obtained via this technique in the regime of relatively high electric fields evidence that the absolute piezoelectric coefficients, |d zi | (i = x, y) show a non-monotonic behavior with an unexpectedly high maximum value |d zi | ~ 1100 pm V−1 at T sin = 1180 °C. These features are accompanied by a progressive increase of coercivity, reaching maximum value E C,i ~ 4.5–5.0 kV cm−1 (i = x, y) at T sin = 1250 °C. To explain these findings, the |d zi | coefficients are compared with the microstructure and compositional information, coming from AFM, Archimedes’ method and XRD data. We conclude that the significantly high |d zi | values observed for samples prepared at T sin = 1180 °C are motivated by the increase of mean GS, <GS>, while for T sin > 1180 °C the decrease of density, ρ, ascribed to the appearance of byproduct phases, dominates and deteriorates |d zi |. These experimental results on |d zi |(T sin) are reliably reproduced by a phenomenological model with reasonable assumptions for <GS> (T sin) and ρ(T sin). The unexpectedly high piezoelectric coefficients, |d zi | ~ 1100 pm V−1, reported here for the first time, are provocative and call for utilization of the introduced approach in the investigation of the respective properties of other compounds.
Composite magnetoelectric compounds that combine ferroelectricity/piezoelectricity and ferromagnetism/magnetostriction are investigated intensively for room-temperature applications. Here, we studied bulk composites of a magnetostrictive constituent, ferromagnetic Fe3O4 nanoparticles, homogeneously embedded in a ferroelectric/piezoelectric matrix, Pb(Zr0.52Ti0.48)O3 (PZT). Specifically, we focused on PZT-5%Fe3O4 samples which are strongly insulating and thus sustain a relatively high out-of-plane external electric field, Eex,z. The in-plane strain-electric field curve (S(Eex,z)) was carefully recorded upon successive application and removal of an out-of-plane external magnetic field, Hex,z. The obtained S(Eex,z) data exhibited two main features. First, the respective in-plane piezoelectric coefficients, d(Eex,z) = 200–250 pm/V, show a dramatic decrease, 50–60%, upon application of a relatively low Hex,z = 1 kOe. Second, the process is completely reversible since the initial value of d(Eex,z) is recovered upon removal of Hex,z. Polarization data, P(Eex,z), evidenced that the Fe3O4 nanoparticles introduced static structural disorder that made PZT harder. Taken together, these results prove that the Fe3O4 nanoparticles, except for static structural disorder, introduce reconfigurable magnetic disorder that modifies the in-plane S(Eex,z) curve and the accompanying d(Eex,z) of PZT when an external magnetic field is applied at will. The room-temperature feasibility of these findings renders the PZT-x%Fe3O4 system a solid basis for the development of magnetic-field-controlled PE devices.
Magnetoelectric (ME) composites that exhibit both ferroelectric and ferromagnetic properties have attracted significant attention, thanks to their potential applications, e.g., low-energy-consumption storage devices. Here, we study bulk composites based on Pb(Zr0.52Ti0.48)O3 (PZT) as a piezoelectric (PE) matrix and Fe3O4 nanoparticles (NPs) as soft ferromagnetic (FM) and magnetostrictive additives, in the form PZT-xFe3O4 with 0% ≤ x ≤ 50 wt. %, all sintered at T = 1000 °C for 2 h in air. We focus our study on a completely insulating sample x = 5% and measure its properties at room temperature upon an out-of-plane external electric field, Eex: namely, piezoelectric response [in-plane strain, S(Eex)], polarization [P(Eex)], and relaxation of the remanent magnetization, [mrem(t,Eex)], prepared upon application and removal of an external magnetic field. The peaks observed in the butterflylike S(Eex) curves at E±peak = ±6 kV/cm and the nucleation field recorded in the P(Eex) loops at the same range around E±nuc = ±6 kV/cm (both referring to the PZT PE matrix) are clearly imprinted on the relaxation behavior of the mrem(t,Eex) data (referring to the Fe3O4 FM NPs). This experimental fact proves the ME coupling between the PZT matrix and the embedded Fe3O4 NPs. We ascribe this feature to the comparable piezoelectricity of the PZT matrix and the magnetostriction of the Fe3O4 NPs that probably motivate and/or promote a strain transfer mechanism occurring at the PZT matrix-Fe3O4 NP interfaces. Our work proves that the low cost PZT-xFe3O4 composite is a promising candidate ME material for future studies, aiming to potential applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.