scholarly journals HP/HT synthesis and characterization of novel multiferroic Bi-based perovskites

2014 ◽  
Vol 70 (a1) ◽  
pp. C1815-C1815
Author(s):  
Davide Delmonte ◽  
Francesco Mezzadri ◽  
Chiara Pernechele ◽  
Massimo Solzi ◽  
Gianluca Calestani ◽  
...  
Keyword(s):  
Data Storage ◽  
Lone Pair ◽  
Solid State Reactions ◽  
Crystallographic Structure ◽  
Scientific Publications ◽  
Increasing Trend ◽  
Magnetic Ions ◽  
Oxygen Anions ◽  
Polar Symmetry

Bi-based perovskites (BiM1-xM'xO3, where M e M' are 3d and 4d metal ions) are considered very promising candidates to show multiferroic magnetoelectric character. A multiferroic magnetoelectric is a material in which ferromagnetism and ferroelectricity are not only coexistent but also coupled. Such properties, very rare in natural materials, are suitable for electronics, data storage and spintronics applications. Therefore, the interest in this class of compound showed an increasing trend of scientific publications in the last ten years. Unfortunately most members of this family cannot be synthesized with conventional techniques, due to their highly unstable and distorted crystallographic structure. High isostatic pressures and high temperatures can be exploited to overcome this fundamental drawback. The strategy is to induce ferroelectricity (e.g. polar symmetry) achieving the stereochemical effect of Bi3+ 6s2 lone pair, that polarizes the bonds with the neighboring oxygen anions, and independently to bring magnetism through the introduction of magnetic ions of the third or the fourth period on the octahedral coordinated B-site of the perovskite structure. We have synthesized simple and complex (quadruple [1,2] and double [3]) Bi-based perovskites in wide ranges of pressure (from 3 to 9 GPa) and temperature (from 9000C to 16500C) by means of solid state reactions in a multi-anvil Walker-type Press. We present an accurate study of the structural, magnetic and electric properties. Furthermore, unconventional home-made set-ups are also presented as the tools to probe the coupling between the electric and the magnetic properties through crossed magnetic characterizations (magnetic susceptibility dependence on an applied electric field) and reversely crossed electric characterizations (polarization as a function of an external magnetic field).

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

scholarly journals Isolation and Molecular Typing of Leishmania infantum from Phlebotomus perfiliewi in a Re-Emerging Focus of Leishmaniasis, Northeastern Italy

2019 ◽  
Vol 7 (12) ◽  
pp. 644
Author(s):  
Mattia Calzolari ◽  
Elena Carra ◽  
Gianluca Rugna ◽  
Paolo Bonilauri ◽  
Federica Bergamini ◽  
...  
Keyword(s):  
Leishmania Infection ◽  
Sand Flies ◽  
Repetitive Region ◽  
Microsatellite Typing ◽  
Increasing Trend ◽  
Northeastern Italy ◽  
Emilia Romagna Region ◽  
Phlebotomus Perfiliewi ◽  
Leishmania Parasites

Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies collected in a re-emerging focus of VL in the Bologna province. During the summer of 2016, 6114 sand flies were collected, identified, and tested for Leishmania detection. Of the identified sand flies, 96.5% were Phlebotomus (P.) perfiliewi and 3.5% were P. perniciosus. Detected parasites were characterized by biomolecular methods (multilocus microsatellite typing and characterization of repetitive region on chromosome 31), and quantified by real-time PCR. The prevalence of Leishmania infection in individually-tested P. perfiliewi sand flies varied from 6% to 10% with an increasing trend during the season. Promastigotes of L. infantum were isolated by dissection in one P. perfiliewi female; the isolated strain (Lein-pw) were closely related to Leishmania parasites from VL cases in northeastern Italy, but differed from strains isolated in dogs from the same area. Our findings strongly support the vector status of P. perfiliewi for human VL in the study area.

scholarly journals Fabrication and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite

e-Polymers ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 038-046
Author(s):  
Xu Yan ◽  
Wanru Zhou ◽  
Xiaojun Ma ◽  
Binqing Sun
Keyword(s):  
Thermal Stability ◽  
Oxygen Permeability ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
Nucleating Agent ◽  
Vapor Permeability ◽  
Casting Method ◽  
Increasing Trend ◽  
Solution Casting Method

Abstract In this study, a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite (MMT/PHBH) was fabricated by solution-casting method. The results showed that the addition of MMT increased the crystallinity and the number of spherulites, which indicated that MMT was an effective nucleating agent for PHBH. The maximum decomposition peak of the biocomposites moved to a high temperature and residue presented an increasing trend. The biocomposites showed the best thermal stability at 1 wt% MMT. Compared with PHBH, 182.5% and 111.2% improvement in elastic modulus and tensile strength were obtained, respectively. Moreover, the oxygen permeability coefficient and the water vapor permeability of MMT/PHBH biocomposites decreased by 43.9% and 6.9%, respectively. It was also found that the simultaneous enhancements on the crystallizing, thermal stability, mechanical, and barrier properties of biocomposites were mainly caused by the formation of intercalated structure between PHBH and MMT.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

scholarly journals Structural characterization of quaternary selenites of tungsten(VI), A 2W3SeO12 (A = NH4, Cs, Rb, K or Tl)

2021 ◽  
Vol 77 (4) ◽  
pp. 406-411
Author(s):  
Vineela Balisetty ◽  
Kanamaluru Vidyasagar
Keyword(s):  
Three Dimensional ◽  
Spectroscopic Studies ◽  
Solid State Reactions ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Compound K ◽  
Three Dimensional Structure ◽  
Thermal And Spectroscopic Studies ◽  
Anionic Framework

The quaternary A 2W3SeO12 (A = NH4, Cs, Rb, K or Tl) selenites have been prepared in the form of single crystals by hydrothermal and novel solid-state reactions. They were characterized by X-ray diffraction, thermal and spectroscopic studies. All of them have a hexagonal tungsten oxide (HTO) related [W3SeO12]2− anionic framework with pyramidally coordinated Se4+ ions. The known A 2W3SeO12 (A = NH4, Cs or Rb) compounds are isostructural with the Cs2W3TeO12 compound and have a non-centrosymmetric layered structure containing intra-layer Se—O bonds. The new compound K2W3SeO12(α) is isostructural with the K2W3TeO12 compound and has a centrosymmetric three-dimensional structure containing interlayer Se—O bonds. It is inferred that the new Tl2W3SeO12 compound has the same three-dimensional structure as K2W3SeO12(α).

scholarly journals A Characterization of the DNA Data Storage Channel

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Reinhard Heckel ◽  
Gediminas Mikutis ◽  
Robert N. Grass
Keyword(s):  
Data Storage

Synthesis and Characterization of Ruteno-Cuprates by Solid State Reactions

2008 ◽  
Vol 591-593 ◽  
pp. 644-648
Author(s):  
J.M.A. Gimenez ◽  
Carlos Roberto Grandini ◽  
A.R. Jurelo
Keyword(s):  
Solid State ◽  
Low Temperatures ◽  
Magnetic Transition ◽  
Solid State Reactions ◽  
Synthesis And Characterization ◽  
Superconducting Properties ◽  
New Class ◽  
Preparation Conditions ◽  
Magnetic States

A new class of hybrid ruteno-cuprates – such as Ru-1212 and Ru-1222 – was discovered in 1995 by Bauerfeind and collaborators. These materials present superconducting and magnetic states at low temperatures, an atypical duality in other superconductors. The superconductivity is more easily observed in Ru-1222, while Ru-1212 is a more problematic case, due to the strong effects of the preparation details in its superconducting properties, becoming the material superconductor or not. Ru-1212 presents a critical temperature that can vary between 0 and 46 K, depending on the preparation conditions, and a temperature of magnetic transition of around 132 K. The samples were prepared through solid state reactions, by using a mixture of high purity powders, followed by calcination and sinterization in the nitrogen and oxygen atmospheres. This paper shows the preparation process of Ru-1212 samples, followed by their structural and magnetic characterization.

scholarly journals The role of fire in UK peatland and moorland management: the need for informed, unbiased debate

2016 ◽  
Vol 371 (1696) ◽  
pp. 20150342 ◽  
Author(s):  
G. Matt Davies ◽  
Nicholas Kettridge ◽  
Cathelijne R. Stoof ◽  
Alan Gray ◽  
Davide Ascoli ◽  
...  
Keyword(s):  
Cultural Landscapes ◽  
Management Tool ◽  
Scientific Publications ◽  
Spatial And Temporal Scales ◽  
Complex Interactions ◽  
Trade Offs ◽  
Response And Recovery ◽  
Benefits And Costs

Fire has been used for centuries to generate and manage some of the UK's cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That fire modifies peatland characteristics at a range of scales is clearly understood. Whether these changes are perceived as positive or negative depends upon how trade-offs are made between ecosystem services and the spatial and temporal scales of concern. Here we explore the complex interactions and trade-offs in peatland fire management, evaluating the benefits and costs of managed fire as they are currently understood. We highlight the need for (i) distinguishing between the impacts of fires occurring with differing severity and frequency, and (ii) improved characterization of ecosystem health that incorporates the response and recovery of peatlands to fire. We also explore how recent research has been contextualized within both scientific publications and the wider media and how this can influence non-specialist perceptions. We emphasize the need for an informed, unbiased debate on fire as an ecological management tool that is separated from other aspects of moorland management and from political and economic opinions. This article is part of the themed issue ‘The interaction of fire and mankind’.

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