With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

Potassium-sodium niobate lead-free piezoelectric materials: past, present, and future of phase boundaries.

Ferroelectrics are essential components in a wide range of applications, including ultrasonic transducers, sensors, and actuators. In the single crystal form, relaxor-PbTiO3 (PT) piezoelectric materials have been extensively studied due to their ultrahigh piezoelectric and electromechanical properties. In this article, a perspective and future development of relaxor-PT crystals are given. Initially, various techniques for the growth of relaxor-PT crystals are reviewed, with crystals up to 100 mm in diameter and 200 mm in length being readily achievable using the Bridgman technique. Second, the characterizations of dielectric and electromechanical properties are surveyed. Boundary conditions, including temperature, electric field, and stress, are discussed in relation to device limitations. Third, the physical origins of the high piezoelectric properties and unique loss characteristics in relaxor-PT crystals are discussed with respect to their crystal structure, phase, engineered domain configuration, macr...

/pdf/high-performance-ferroelectric-relaxor-pbtio3-single-3cp5am04w0.pdf

High performance ferroelectric relaxor-PbTiO3 single crystals: Status and perspective

We present a critical review that encompasses the fundamentals and state-of-the-art knowledge of barium titanate-based piezoelectrics. First, the essential crystallography, thermodynamic relations, and concepts necessary to understand piezoelectricity and ferroelectricity in barium titanate are discussed. Strategies to optimize piezoelectric properties through microstructure control and chemical modification are also introduced. Thereafter, we systematically review the synthesis, microstructure, and phase diagrams of barium titanate-based piezoelectrics and provide a detailed compilation of their functional and mechanical properties. The most salient materials treated include the (Ba,Ca)(Zr,Ti)O3, (Ba,Ca)(Sn,Ti)O3, and (Ba,Ca)(Hf,Ti)O3 solid solution systems. The technological relevance of barium titanate-based piezoelectrics is also discussed and some potential market indicators are outlined. Finally, perspectives on productive lines of future research and promising areas for the applications of these ma...

BaTiO3-based piezoelectrics: Fundamentals, current status, and perspectives

Recent development in lead-free perovskite piezoelectric bulk materials

Preparation and characterization of sol-gel derived (100)-textured Pb(Zr, Ti)O3 thin films: PbO seeding role in the formation of preferential orientation

Lead zirconate titanate [Pb(ZrxTi1−x)O3, PZT] thin films with various compositions, whose Zr/Ti ratio were varied as 40/60, 48/52, 47/53, and 60/40, were deposited on Pt(111)/Ti/SiO2/Si substrates by sol-gel method. A seeding layer was introduced between the PZT layer and the bottom electrode to control the texture of overlaid PZT thin films. A single perovskite PZT thin film with absolute (100) texture was obtained, when lead oxide was used as the seeding crystal, whereas titanium dioxide resulted in highly [111]-oriented PZT films. The dielectric and ferroelectric properties of PZT films with different preferential orientations were evaluated systemically as a function of composition. The maximums of relative dielectric constant were obtained in the morphotropic phase boundary region for both (100)- and (111)-textured PZT films. The ferroelectric properties also greatly depend on films’ texture and composition. The intrinsic and extrinsic contributions to dielectric and ferroelectric properties were dis...

Combined effect of preferential orientation and Zr/Ti atomic ratio on electrical properties of Pb(ZrxTi1−x)O3 thin films

Lead zirconate titanate (PZT) films with composition near the morphotropic phase boundary were fabricated on Pt(111)/Ti/SiO 2 /Si(100) using sol-gel method, and the pyrolysis temperature effects on the preferential orientation and ferroelectric properties of PZT films were investigated It has been found that the PZT films pyrolyzed at 450 °C and then annealed at 650 °C shown a dominated (100) orientation, whereas the pyrolysis treatment at lower or higher temperatures favored the (111) orientation Different pyrolysis temperatures also lead to differences in electrical properties, including dielectric constant, polarization values, leakage current and fatigue behavior

Effect of pyrolysis temperature on preferential orientation and electrical properties of sol-gel derived lead zirconate titanate films

(Pb0.97La0.02)(ZrxSn0.94–xTi0.06)O3 (PLZST) antiferroelectric ceramics with x = 0.75–0.90 have been fabricated and found to be a novel electrocaloric material system with a giant negative electrocaloric effect (ΔT = −11.5 K) and a large electrocaloric strength (|ΔT/ΔE| = 0.105 K cm kV–1) near room temperature. Additionally, the PLZST antiferroelectric ceramic also exhibits a large positive electrocaloric effect around the Curie temperature. The giant negative effect and the coexistence of both positive and negative electrocaloric effects in one material indicate a promising possibility to develop mid- to large-scale solid-state cooling devices with high efficiency.

Giant Negative Electrocaloric Effect in (Pb,La)(Zr,Sn,Ti)O3 Antiferroelectrics Near Room Temperature.

Single-crystal Nb-doped Pb(Zr,Ti)O3 (PNZT) films were grown on electric conducting single-crystal Nb-doped SrTiO3 (Nb:STO) wafers by a sol-gel method. Although the films were of the same composition and prepared under the same condition, different crystal phases with corresponding preferential film orientations were formed when the substrate orientation was changed. [001]-oriented tetragonal PNZT film was formed on the {100} surface of the Nb:STO substrate, whereas [111]-oriented rhombohedral PNZT film on the {111} surface. The PNZT films on SrTiO3 substrates showed considerably high remnant polarization and low coercive field, as compared with conventional PZT films on Si wafers. In particular, high d33 value was obtained in the [001]-oriented PNZT films.

Xiangcheng Chu

Papers

Preparation and characterization of sol-gel derived (100)-textured Pb(Zr, Ti)O3 thin films: PbO seeding role in the formation of preferential orientation

Combined effect of preferential orientation and Zr/Ti atomic ratio on electrical properties of Pb(ZrxTi1−x)O3 thin films

Effect of pyrolysis temperature on preferential orientation and electrical properties of sol-gel derived lead zirconate titanate films

Giant Negative Electrocaloric Effect in (Pb,La)(Zr,Sn,Ti)O3 Antiferroelectrics Near Room Temperature.

Single-crystal Nb-doped Pb(Zr,Ti)O3 thin films on Nb-doped SrTiO3 wafers with different orientations