The piezoelectric properties of lead zirconate titanate [Pb(Zr,Ti)O ₃ or PZT] ceramics could be enhanced by fabricating textured ceramics that would align the crystal grains along specific orientations. We present a seed-passivated texturing process to fabricate textured PZT ceramics by using newly developed Ba(Zr,Ti)O ₃ microplatelet templates. This process not only ensures the template-induced grain growth in titanium-rich PZT layers but also facilitates desired composition through interlayer diffusion of zirconium and titanium. We successfully prepared textured PZT ceramics with outstanding properties, including Curie temperatures of 360°C, piezoelectric coefficients d ₃₃ of 760 picocoulombs per newton and g ₃₃ of 100 millivolt meters per newton, and electromechanical couplings k ₃₃ of 0.85. This study addresses the challenge of fabricating textured rhombohedral PZT ceramics by suppressing the otherwise severe chemical reaction between PZT powder and titanate templates.

Relaxor-lead titanate (PbTiO₃) crystals, which exhibit extremely high piezoelectricity, are believed to possess high electro-optic (EO) coefficients. However, the optical transparency of relaxor-PbTiO₃crystals is severely reduced as a result of light scattering and reflection by domain walls, limiting electro-optic applications. Through synergistic design of a ferroelectric phase, crystal orientation, and poling technique, we successfully removed all light-scattering domain walls and achieved an extremely high transmittance of 99.6% in antireflection film–coated crystals, with an ultrahigh EO coefficientr₃₃of 900 picometers per volt (pm V⁻¹), >30 times as high as that of conventionally used EO crystals. Using these crystals, we fabricated ultracompact EO Q-switches that require very low driving voltages, with superior performance to that of commercial Q-switches. Development of these materials is important for the portability and low driving voltage of EO devices.

For the first time, this work presents a novel room temperature time-effective concept to manipulate the crystallization kinetics and magnetic responses of thin films grown on amorphous substrates. Conventionally, metal-induced crystallization is adopted to minimize the crystallization temperature of the upper-layer thin film. However, due to the limited surface area of the continuous metal under-layer, the degree of crystallization is insufficient and post-annealing is required. To expose a large surface area of the metal under-layer, we propose a simple and novel approach of using an Au nanodots array instead of a continuous metallic under-layer to obtain crystallization of upper-layer thin films. Spinel cobalt ferrite (CFO) thin film as a ‘model’ was deposited on an Au nano-dots array to realize this methodology. Our findings revealed that the addition of quantum-sized Au nano-dots as a metal under-layer dramatically enhanced the crystallization of the cobalt ferrite upper layer at room temperature. The appearance of major X-ray diffraction peaks with high intensity and well-defined crystallized lattice planes observed via transmission electron microscopy confirmed the crystallization of the CFO thin film deposited at room temperature on 4 nm-sized Au nano-dots. This crystallized CFO thin film exhibits 18-fold higher coercivity (H_c = 4150 Oe) and 4-fold higher saturation magnetization (M_s = 262 emu cm⁻³) compared to CFO deposited without the Au under-layer. The development of this novel concept of room-temperature crystallization without the aid of additives and solvents represents a crucial breakthrough that is highly significant for exploring the green and energy-efficient synthesis of a variety of oxide and metal thin films.

We report the synthesis and characterization of ordered multiferroic $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ (BFO) nanotube arrays. BFO nanotubes with diameters of about $250\mathrm{nm}$ and lengths of about $6\mu \mathrm{m}$ were fabricated by means of a sol-gel method utilizing nanochannel alumina templates. After postannealing at $700°\mathrm{C}$ , the BFO nanotubes exhibited a polycrystalline microstructure, and x-ray diffraction and transmission electron microscopy study revealed that they are of a perovskite crystal structure. Significant ferroelectric and piezoelectric characteristics of BFO nanotubes have been demonstrated by means of piezoresponse force microscopy measurement.