Author
G. Prasad
Bio: G. Prasad is an academic researcher from Osmania University. The author has contributed to research in topics: Dielectric & Ceramic. The author has an hindex of 13, co-authored 132 publications receiving 767 citations.
Topics: Dielectric, Ceramic, Ferroelectricity, Conductivity, Bismuth titanate
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the phase identification, morphology, thermal expansion and electrical properties of samples were studied by XRD, SEM, Dilatometry and Impedance spectroscopy.
71 citations
TL;DR: In this article, the spin-Hamiltonian parameters of rare earth borates were derived from the ESR spectra of Lanthanide orthoborates of composition LnBO{sub 3] (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y, Y) and La, Tb and Eu have been prepared by metathesis reaction This method provides a convenient route for the synthesis of orthoborsates and its solid solutions at low temperatures powder X-ray diffraction and FT-
49 citations
TL;DR: In this article, two types of conduction processes are evident from the frequency dependant conductivity plots, i.e., low-frequency conduction due to short-range hopping and high-frequency convolutional hopping mechanism.
Abstract: Electrical conduction studies on Ba(Nd0.2Ti0.6Nb0.2)O3 ceramic samples prepared through conventional and microwave sintering route are presented in this paper. D.C. and a.c. conductivities of these samples as a function of temperature from 300–900 K have been studied. Two types of conduction processes are evident from the frequency dependant conductivity plots, i.e. low-frequency conduction due to short-range hopping and high-frequency conduction due to the localized relaxation (reorientational) hopping mechanism. Grain and grain boundary contributions to the conductivity in these samples are obtained from impedance/admittance measurements via equivalent circuit modelling.
45 citations
TL;DR: In this paper, the structure, ferroelectric and photocatalytic activities of co-doped Bi4Ti3O12 (SBVT) ceramics were analyzed by SEM and HRTEM studies.
Abstract: We performed a systematic analysis of the structure, ferroelectric and photocatalytic activities of Sm and V co-doped Bi4Ti3O12 (SBVT) ceramics. The formation of 3-layered Aurivillius structure and chemically induced strain of SBVT were analyzed by SEM and HRTEM studies. From the results of structural refinements, temperature dependent XRD and Raman spectra we found that SBVT has a distorted orthorhombic structure and transforms to tetragonal in the temperature range of 475–600 °C. Raman modes of Bi sites experience the phase transition earlier compared to torsional bending modes of BO6 octahedra. From the results of polarization and piezoelectric strain measurements, we found that SBVT exhibits superior ferroelectric characteristics as well as improved S33 (0.02 × 10−3) compared to other rare-earth doped Bi4Ti3O12 materials reported in the literature. SBVT exhibited fatigue endurance up to 108 switching cycles. Such a behavior is attributed to the structural distortions due to the smaller ionic radius of Sm3+ and reduced oxygen vacancies. Local piezoresponse measurements demonstrated imprint characteristics of ferroelectric domains. Furthermore, we assessed the photocatalytic (PC) activity of SBVT – for the first time – in the gas–solid phase, monitoring the degradation of nitrogen oxides (i.e. NO + NO2). Results demonstrated that SBVT was photocatalytically active in the solar spectrum, being able to degrade NOx at ppb level concentration, and exhibited a very stable PC activity (five consecutive PC runs), proving itself suitable for reuse.
39 citations
TL;DR: In this article, lead-free piezoelectric ceramic composites (1-x) Na0.5Bi 0.5TiO3-xSrTiOO3, where x = 0.05, 0.10,0.15 and 0.2, are prepared by mixing independently-prepared individual phases through sol-gel method.
Abstract: Lead-free piezoelectric ceramic composites (1-x) Na0.5Bi0.5TiO3-xSrTiO3, where x = 0.05, 0.10, 0.15 and 0.2, are prepared by mixing independently-prepared individual phases through sol–gel method. X-ray diffraction revealed the coexistence of rhombohedral and cubic phases. Surface morphology of the composites is observed using SEM, and both the phases are observed in the samples. Spectroscopic studies of the composites are characterized based on Fourier transform infrared, and vibration bands are analyzed at room temperature in the wave number region 500–3,000 cm−1. Dielectric properties of these composites are measured from room temperature to 400 °C in the frequency range 1–10 kHz, and these studies indicate the presence of defect clusters within the composite materials. P–E hysteresis loops of these samples were measured as a function of temperature and observed large anomalies in the behavior compared to pure sodium bismuth titanate (NBT) (the host material). Unlike NBT, all the composites exhibited excellent P–E loops. In addition, decrease in remanence polarization is observed, with increase of SrTiO3 at room temperature. Piezoelectric parameter d33 is measured on poled composites.
25 citations
Cited by
More filters
TL;DR: In this article, the authors reviewed the recent developments on lead-free piezo materials emphasizing on their preparation, structure-property correlation, etc., and concluded that some lead free compositions show stable piezoelectric responses even though they do not match the overall performance of PZT.
Abstract: Lead zirconate titanate (PZT) based piezoelectric materials are well known for their excellent piezoelectric properties. However, considering the toxicity of lead and its compounds, there is a general awareness for the development of environmental friendly lead-free materials as evidenced from the legislation passed by the European Union in this effect. Several classes of materials are now being considered as potentially attractive alternatives to PZTs for specific applications. In this paper, attempts have been made to review the recent developments on lead-free piezo materials emphasizing on their preparation, structure–property correlation, etc. In this context, perovskite systems such as bismuth sodium titanate, alkali niobates (ANbO3), etc. and non-perovskites such as bismuth layer-structured ferroelectrics are reviewed in detail. From the above study, it is concluded that some lead-free compositions show stable piezoelectric responses even though they do not match the overall performance of PZT. This has been the stimulant for growing research on this subject. This topic is of current interest to the researchers worldwide as evidenced from the large number of research publications. This has motivated us to come out with a review article with a view that it would give further impetus to the researchers already working in this area and also draw the attention of the others.
865 citations
694 citations
TL;DR: A wide range of materials based on crystalline and glassy Nasicon compositions are considered in this paper, and their structure, compositional diversity, evolution, and applications are reviewed.
Abstract: Nasicons (sodium super ion conductors) are a class of solid electrolytes. Their structure, compositional diversity, evolution, and applications are reviewed. A wide range of materials is considered based on crystalline and glassy Nasicon compositions.
407 citations
TL;DR: This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5TiO 3, Na 0.5Bi0.4NbO3 and their solid solutions.
Abstract: Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3 (PZT),are comprised of more than 60 weight percent lead (Pb). Dueto its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.
398 citations