Structural and Electrical Characteristics of FeTiVO6 Double Perovskite

In this paper, studies of structural as well as electrical characteristics of the double perovskite material FeTiVO6 (iron titanium vanadate), synthesized by a high-temperature mixed oxide reaction method have been discussed. The room temperature X-ray diffraction analysis confirms the formation of a single-phase orthorhombic structure without any secondary phase. All the electrical characteristics (i.e., dielectric, impedance, conductivity and modulus) of the sample, studied at various temperatures (25–300°C) and frequencies (1[Formula: see text]kHz–1[Formula: see text]MHz), provide many remarkable characteristics of the material. The dielectric parameters as a function of frequency explain the presence of different polarization mechanisms based on the Maxwell–Wagner double-layer model. Impedance analysis describes the grain (bulk) and grain boundary (bulk interior) effect on the material using the equivalent RQC-RC circuits. The presence of non-Debye type of relaxation behavior in the material is confirmed by the depressed semicircles of Nyquist plots. The conductivity study provides information about the CBH and OLPT type of conduction phenomenon. The temperature dependence of leakage current behavior follows the Ohmic (semiconductor) and space charge limited conduction mechanisms at a different range of applied fields. The occurrence of the room temperature hysteresis loop obtained from the PE loop tracer confirms the ferroelectric behavior of the studied compound.

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Studies of Structural and Electrical Characteristics of Multi-substituted Bi0.5Na0.5TiO3 Ferroelectric Ceramics

10.21203/rs.3.rs-292550/v1 ◽

2021 ◽

Author(s):

B. B. Arya ◽

R N P Choudhary

Keyword(s):

Room Temperature ◽

Boundary Effect ◽

Parent Compound ◽

Solid State Reaction Method ◽

Ferroelectric Ceramics ◽

Temperature Hysteresis ◽

Positive Temperature ◽

Electrical Characteristics ◽

General Chemical ◽

Wide Range

Abstract In this communication, preliminary structural and detailed electrical characteristics of the CaSnO3/CaSeO3 modified Bi0.5Na0.5TiO3 ceramics of a general chemical composition (1–2x) [Bi0.5Na0.5TiO3] + x (CaSnO3) + x (CaSeO3) with x= 0, 0.05, 0.10, 0.15, prepared by high- temperature solid-state reaction method with calcination and sintering temperature 925 oC and 950oC respectively for 5 h, have been reported. Structural and electrical characteristics of the parent compound have significantly been tailored by the addition of the equal percentage of CaSnO3, CaSeO3 over a wide range of temperature (25oC - 400 oC) as well as frequency (1 kHz-1MHz). Analysis of room temperature X-ray diffraction (XRD) data confirmed the development of single-phase compound (with rhombohedral symmetry) with very small amount of impurity phase with higher concentrations (x). In the dielectric spectroscopy, two dielectric peaks are observed at around temperatures 210 oC and 320 oC indicating multiple phase transitions of different types including the ferroelectric to para-electric through anti-ferroelectric. Impedance analysis of data exhibits both negative/positive temperature coefficient of temperature (i.e., semiconductor behavior) of the materials. The Nyquist plots determine the grain and grain boundary effect in capacitive and resistive properties of the materials, and also the non-Debye type of relaxation. The room temperature hysteresis loop confirms the existence of ferroelectricity in the materials. The leakage current characteristics also determine the Ohmic behavior of the materials.

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Room-temperature Ferroelectricity and Ferromagnetism in Double Perovskite Bi2CoMnO6 Ceramics Synthesized Using Sol–Gel Combustion Technique

Journal of Superconductivity and Novel Magnetism ◽

10.1007/s10948-021-05947-2 ◽

2021 ◽

Author(s):

Rajnish Kurchania ◽

Riya Sahu ◽

Kumar Navin ◽

Oroosa Subohi

Keyword(s):

Room Temperature ◽

Sol Gel ◽

Double Perovskite ◽

Gel Combustion ◽

Combustion Technique

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Influence of the ultra-slow nucleation and growth dynamics on the room-temperature hysteresis of spin-crossover single crystals

Chemical Physics Letters ◽

10.1016/j.cplett.2021.138442 ◽

2021 ◽

pp. 138442

Author(s):

Volodymyr M. Hiiuk ◽

Karl Ridier ◽

Il'ya A. Gural'skiy ◽

Alexander A. Golub ◽

Igor O. Fritsky ◽

...

Keyword(s):

Single Crystals ◽

Room Temperature ◽

Spin Crossover ◽

Growth Dynamics ◽

Nucleation And Growth ◽

Temperature Hysteresis

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The Deformation Behavior and Bending Emissions of ZnO Microwire Affected by Deformation-Induced Defects and Thermal Tunneling Effect

Sensors ◽

10.3390/s21175887 ◽

2021 ◽

Vol 21 (17) ◽

pp. 5887

Author(s):

Linlin Shi ◽

Hong Wang ◽

Xiaohui Ma ◽

Yunpeng Wang ◽

Fei Wang ◽

...

Keyword(s):

Room Temperature ◽

Luminescent Properties ◽

Tunneling Effect ◽

Light Sources ◽

Electrical Characteristics ◽

Fundamental Research ◽

Induced Defects ◽

Theoretical Simulations ◽

Bright Emission

The realization of electrically pumped emitters at micro and nanoscale, especially with flexibility or special shapes is still a goal for prospective fundamental research and application. Herein, zinc oxide (ZnO) microwires were produced to investigate the luminescent properties affected by stress. To exploit the initial stress, room temperature in situ elastic bending stress was applied on the microwires by squeezing between the two approaching electrodes. A novel unrecoverable deformation phenomenon was observed by applying a large enough voltage, resulting in the formation of additional defects at bent regions. The electrical characteristics of the microwire changed with the applied bending deformation due to the introduction of defects by stress. When the injection current exceeded certain values, bright emission was observed at bent regions, ZnO microwires showed illumination at the bent region priority to straight region. The bent emission can be attributed to the effect of thermal tunneling electroluminescence appeared primarily at bent regions. The physical mechanism of the observed thermoluminescence phenomena was analyzed using theoretical simulations. The realization of electrically induced deformation and the related bending emissions in single microwires shows the possibility to fabricate special-shaped light sources and offer a method to develop photoelectronic devices.

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NaFePO4 Cathode Prepared from The Caustic Fusion of A Mix Ilmenite-Hematite Followed by Cyclic Voltammetry for Na Insertion

The Journal of Pure and Applied Chemistry Research ◽

10.21776/ub.jpacr.2020.009.02.527 ◽

2020 ◽

Vol 9 (2) ◽

pp. 142-152

Author(s):

Fitria Rahmawati ◽

◽

Dwi Aman Nur Romadhona ◽

Syulfi Faiz ◽

◽

...

Keyword(s):

Electrical Conductivity ◽

Cyclic Voltammetry ◽

Secondary Phase ◽

Impedance Analysis ◽

Fusion Method ◽

Peak Point ◽

Fe Content ◽

Scan Rate ◽

Hematite Fe2o3 ◽

Resistance Value

Research to prepare NaFePO4 cathode material from iron sand was conducted. The iron sand consists of ilmenite FeTiO3 and hematite Fe2O3. A caustic fusion method used to precipitate iron as Fe(OH)3 and it increased Fe content up to 94.71 %. Phosphate precipitation successfully produced trigonal FePO4 and monoclinic FePO4 comply with ICSD#412736 and ICSD#281079. The prepared-FePO4 was then used as a precursor for Na insertion by applying cyclic voltammetry mode within 2.0 – 4.0 V with 0.05 mVs-1 of the scan rate. It produced orthorhombic olivine NaFePO4 and a secondary phase of orthorhombic Na0.7FePO4. Impedance analysis at 20 Hz – 5 MHz found that the material provided a semicircle at 100 Hz peak point, indicating electrode-bulk interface with a resistance value of 1735W, comparable to the electrical conductivity of 5.36 x 10-6 Scm-1. Even though the conductivity value is quite lower than NaFePO4 prepared from a commercial FePO4 that has been conducted in our previous research, however the electrical conductivity still reliable for cathode.

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Improving photoluminescence, optical and electrical characteristics of PMMA films with gamma irradiation

Physica Scripta ◽

10.1088/1402-4896/ac454d ◽

2021 ◽

Author(s):

M.F. Zaki ◽

Nasser Shubayr ◽

Reda M Radwan ◽

Yazeed Alashban

Keyword(s):

Gamma Irradiation ◽

Polymeric Materials ◽

Advanced Materials ◽

Strong Impact ◽

Electrical Characteristics ◽

Electrical Measurements ◽

Indirect Transition ◽

Dielectric Parameters ◽

Vis Spectroscopy ◽

Gamma Irradiated

Abstract Polymeric materials are macromolecules, essentially a combination of numerous repeated subunits. Polymers are innovative and advanced materials that currently have a strong impact on our daily lives. In recent years, polymer use has been prominent due to the materials’ distinctive properties; thus, they entered different fields of science, technology and industrial-biomedical applications.The improvement of photoluminescence, optical and electrical characteristics of non-conducting Poly(methyl methacrylate) (PMMA) films was studied. Upon gamma irradiation of various doses, the photophysical and electrical properties of PMMA films were investigated using photoluminescence spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy and the LCR Meter Bridge Circuit technique. The fluorescent response improved the photoluminescence (PL) spectral emission peaks according to gamma values. Strong fluorescence peaks appeared with the highest gamma dose. The UV–Vis results revealed a significant red-shift in the absorption edge as gamma doses increased. This shift exhibits a continuous decrease in the energy band gap values (from 3.50 to 2.60 eV for direct transition and from 3.05 to 1.55 eV for indirect transition). This was due to the formation of carbon clusters, which led to an increase in the electrical conductivity and improved the dielectric parameters of the irradiated PMMA films. Among a variety of measurements presented and discussed in the present study, the electrical measurements showed improved electrical characteristics of gamma-irradiated PMMA films.

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