Bio: T.K. Dey is an academic researcher from Indian Institute of Technology Kharagpur. The author has contributed to research in topics: Electrical resistivity and conductivity & Seebeck coefficient. The author has an hindex of 13, co-authored 36 publications receiving 415 citations.
TL;DR: In this article, the Curie temperature (T C ) of the prepared samples is found to be strongly dependent on K content and spans between 260 and 309 K. The maximum magnetic entropy change observed for samples with different concentration of K, exhibits a linear dependence with the applied magnetic field.
TL;DR: In this article, the authors investigated the properties of a series of monovalent (K) doped La 1− x K x MnO 3 polycrystalline pellets prepared by pyrophoric method.
TL;DR: In this article, the magnetic properties of fine grained perovskite manganites of the type La0.7Ba0.3−zNazMnO3 have been investigated.
TL;DR: In this article, nano-mechanical properties of high-density polyethylene (HDPE) thermoplastic polymer-matrix fabricated by melt-blending, compression molding followed by hot pressing are investigated.
TL;DR: In this paper, the lower limit of G.L. breakdown temperature appears to be strongly dependent on the silver concentration in YBa2Cu3.05Ox pellets and the critical exponent of critical exponent = −0.28.
TL;DR: In this paper, the influence of nanoparticle selection, production process, grain size, and grain boundary structures on the mechanical properties of nanomaterials is introduced, and the current research progress and application range of nano-materials are presented.
Abstract: Abstract As an emerging material, nanomaterials have attracted extensive attention due to their small size, surface effect and quantum tunneling effect, as well as potential applications in traditional materials, medical devices, electronic devices, coatings and other industries. Herein, the influence of nanoparticle selection, production process, grain size, and grain boundary structures on the mechanical properties of nanomaterials is introduced. The current research progress and application range of nano-materials are presented. The unique properties of nano-materials make them superior over traditional materials. Therefore, nanomaterials will have a broader application prospect in the future. Research on nanomaterials is significant for the development and application of materials science.
TL;DR: This extensive review analyzes the literature covering broad topical areas under solid-state low temperature thermal energy harvesting, which will provide guidance towards designing a hybrid thermal energy harvester that can overcome various limitations of the individual mechanism.
Abstract: Combined rejected and naturally available heat constitute an enormous energy resource that remains mostly untapped. Thermal energy harvesting can provide a cost-effective and reliable way to convert available heat into mechanical motion or electricity. This extensive review analyzes the literature covering broad topical areas under solid-state low temperature thermal energy harvesting. These topics include thermoelectricity, pyroelectricity, thermomagneticity, and thermoelasticity. For each topical area, a detailed discussion is provided comprising of basic physics, working principle, performance characteristics, state-of-the-art materials, and current generation devices. Technical advancements reported in the literature are utilized to analyze the performance, identify the challenges, and provide guidance for material and mechanism selection. The review provides a detailed analysis of advantages and disadvantages of each energy harvesting mechanism, which will provide guidance towards designing a hybrid thermal energy harvester that can overcome various limitations of the individual mechanism.
01 Mar 2001
TL;DR: The doping dependence of the orientation, commensuration, and coherence length of the polaron correlations are established and it is shown that the populations of correlated and uncorrelated polarons are intimately related to the transport properties of the materials.
Abstract: We use neutron scattering to demonstrate the presence of lattice polarons and their short-range correlations for several samples of La1-xCaxMnO3 in the Ca doping range 0.15=x=0.3. We establish the doping dependence of the orientation, commensuration, and coherence length of the polaron correlations and show that the populations of correlated and uncorrelated polarons are intimately related to the transport properties of the materials.
TL;DR: A review of the literature on substitutions and their effect on the properties of the 90 K superconductor YBa 2 Cu 3 O δ (YBCO) can be found in this paper.
Abstract: The 90 K superconductor, YBa 2 Cu 3 O δ (YBCO), has proved to be highly adaptable chemically as it can accommodate a wide variety of cationic and anionic substitutions. Indeed, the majority of the chemical elements, excluding noble gases and actinides, have been reported to substitute to some extent into the YBCO structure. This review covers the literature on such substitutions and their effect on the properties of YBCO. Reported solubility limits are given, together with crystal symmetry and trends in unit cell parameters with dopant concentration. The dopant site is considered; this is additionally complex in the case of copper substitution because of the two distinct copper sites in the crystal structure. The effect of the dopant on the critical temperature, T c , is reviewed; the literature is often contradictory due to the dual effects of variable oxygen content and the nature of the dopant. Preparation methods appear to have an effect on solubility limits, crystal symmetry and T c , Also, the methods used to determine solubility limits are often imprecise which can lead to contradictions. The magnetic properties of doped materials are reviewed; for some dopants, particularly the magnetic lanthanides, antiferromagnetism and superconductivity co-exist. The related RBa 2 Cu 3 O δ phases (R = lanthanide), their structure, properties and behaviour on doping are reviewed in a similar way. For the larger rare earths, the related systems R 1+ x Ba 2- x CU 3 O δ , are reviewed; as x increases, the transition temperature decreases and compositions R 1.5 Ba 1.5 Cu 3 O δ are semiconducting. The upper and lower solubility limit changes with R, and for R = Dy, the upper limit is x = 0 composition, LaBa 2 Cu 3 O δ , cannot be prepared in air since substitution of La onto the Ba site occurs, forming the Ba-deficient solid solutions. The discovery of superconductivity above liquid nitrogen temperatures in YBa 2 Cu 3 O 7 , has generated a vast quantity of research; to date, > 20 000 papers have appeared on the 123 materials (source: BIDS). This review, therefore, cannot be comprehensive, but attempts to highlight important substitutions, their effect on the properties of YBCO and any contradictions in the literature.
TL;DR: In this paper, the authors discuss the synthesis of various types of cuprate superconductors and point out the advantages and disadvantages of the different methods and points out the disadvantages of different methods.
Abstract: A variety of synthetic strategies has been employed to prepare pure monophasic cuprates of different families with good superconducting properties. Besides the traditional ceramic method, other methods such as coprecipitation and precursor methods, the sol-gel method, the alkali flux method and the combustion method have been employed for the synthesis of cuprates. Depending on the requirements, varying conditions such as high oxygen or hydrostatic pressure and low oxygen fugacity are employed in the synthesis. In this review, the authors discuss the synthesis of the various types of cuprate superconductors and point out the advantages and disadvantages of the different methods.