DIELECTRIC PROPERTIES OF Ni2+ AND Mn3+ SUBSTITUTED Li-FERRITE PREPARED BY MICROWAVE SINTERING TECHNIQUE

2007 ◽  
Vol 21 (08) ◽  
pp. 497-503 ◽  
Author(s):  
MAMATA MAISNAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
L. RADHAPIYARI DEVI ◽  
O. P. THAKUR ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Comparative Study ◽  
Lattice Constant ◽  
Spinel Structure ◽  
Single Phase ◽  
Microwave Sintering ◽  
Dielectric Behavior ◽  
Phase Spinel ◽  
Xrd Studies

Li 0.45 Ni 0.1 Mn 0.1 Fe 2.35 O 4 ferrite samples were prepared by microwave-sintering (MS) and conventional (CS) techniques. XRD studies have confirmed the single-phase spinel structure of the sample. The lattice constant was found to be 8.334 Å which is lower than that of the conventionally sintered (CS) sample. Upon microwave sintering, improved physical and electrical properties (like density, resistivity etc.) were obtained. A comparative study has been made on the dielectric behavior of samples processed by both techniques. The possible mechanisms are discussed.

ELECTRICAL CONDUCTION IN SUBSTITUTED Li-FERRITES PREPARED BY MICROWAVE PROCESSING

2005 ◽  
Vol 19 (21) ◽  
pp. 1051-1055 ◽  
Author(s):  
MAMATA MAISNAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
CHANDRA PRAKASH ◽  
L. RADHAPIYARI DEVI ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lattice Constant ◽  
Electrical Conduction ◽  
Spinel Structure ◽  
Single Phase ◽  
Microwave Sintering ◽  
Microwave Processing ◽  
Conventional Sintering

Samples with representative formula Li 0.45 Ni 0.1 Mn 0.1 Fe 2.35 O 4 have been sintered by conventional sintering technique and microwave sintering technique. Both the samples showed single-phase with spinel structure. The lattice constant for the microwave sintered (MS) sample showed a lower value than the conventionally sintered (CS) sample. The density of the MS sample has been found to be higher than the CS sample. And MS sample showed a higher value of resistivity and activation energy compared to the CS sample. The possible mechanisms are discussed.

ELECTRICAL PROPERTIES OF Cd2+ SUBSTITUTED Li–Zn FERRITES

2010 ◽  
Vol 24 (20) ◽  
pp. 2195-2200 ◽  
Author(s):  
MAMATA MAISNAM ◽  
SUMITRA PHANJOUBAM ◽  
CHANDRA PRAKASH
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Curie Temperature ◽  
Lattice Constant ◽  
Spinel Structure ◽  
Single Phase ◽  
Dc Resistivity ◽  
Constant Density ◽  
Zn Ferrite

Cd 2+ substituted Li – Zn ferrite with compositional formula Li 0.4-x/2 Zn 0.2 Cd x Fe 2.4-x/2 O 4 with x = 0.02, 0.03 and 0.04 were prepared by the conventional double sintering ceramic technique. XRD technique confirmed the formation of single phase with spinel structure. The substitution causes an increase in the lattice constant, density and DC resistivity, while the Curie temperature and dielectric constant decreases with Cd 2+ substitution. The mechanisms involved are discussed.

Study on Ferroelectric and Dielectric Properties of Zr-Doped Sr2Bi4Ti5O18 Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 248-251 ◽  
Author(s):  
Ji Gong Hao ◽  
Zhi Jun Xu ◽  
Rui Qing Chu ◽  
Yan Jie Zhang ◽  
Qian Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Single Phase ◽  
Piezoelectric Properties ◽  
Ferroelectric Ceramics ◽  
Sem Images ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
Curie Temperature Tc ◽  
Ferroelectric And Piezoelectric Properties

Zr-doped Sr2Bi4Ti5O18 (SBTi) bismuth layer-structured ferroelectric ceramics were prepared and studied. XRD patterns revealed that all the ceramic samples were single phase compounds. SEM images showed that dense microstructures with uniform gain size were obtained in all samples. The effects of Zr4+ doping on the dielectric, ferroelectric and piezoelectric properties of SBTi ceramics were also investigated. It was found that Zr4+ dopant gradually decreased the Curie temperature (Tc), enhanced the remnant polarization (2Pr) and decreased the coercive field (Ec) of SBTi ceramics. Furthermore, the piezoelectric properties of the SBTi ceramics were improved by enlarging the content of Zr. The SBTi ceramics with 4 mol% of Zr4+ dopant exhibited good electrical properties: d33 = 21 pC/N, 2Pr = 14.3 μC/cm2, Tc = 251°C, εr = 376, tanδ = 1.8%.

scholarly journals A Comparative Study of Spinel ZnFe2O4 Ferrites Obtained via a Hydrothermal and a Ceramic Route: Structural and Magnetic Properties

2020 ◽  
Author(s):  
Xuesong Zhu ◽  
Chunxiang Cao ◽  
Shubing Su ◽  
A.L. Xia ◽  
Huiyan Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Comparative Study ◽  
Spinel Structure ◽  
Single Phase ◽  
Hydrothermal Process ◽  
Ceramic Method ◽  
Mixed Spinel ◽  
Structural And Magnetic Properties ◽  
Ceramic Route ◽  
Fe Ions

Abstract The spinel ZnFe2O4 specimens were obtained via a hydrothermal and a ceramic method, respectively, and their structural and magnetic properties were comparatively studied. It was found that all the specimens exhibited a single-phase and mixed spinel structure. The magnetism of specimens synthesized via the hydrothermal method is obviously greater than that of specimen prepared via the ceramic method. This can be ascribed to the occupancy of Fe ions resulted from the loss of Zn during the hydrothermal process.

scholarly journals Significantly Improved Colossal Dielectric Properties and Maxwell—Wagner Relaxation of TiO2—Rich Na1/2Y1/2Cu3Ti4+xO12 Ceramics

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6043
Author(s):  
Pariwat Saengvong ◽  
Narong Chanlek ◽  
Bundit Putasaeng ◽  
Atip Pengpad ◽  
Viyada Harnchana ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Molar Ratio ◽  
Boundary Density ◽  
Dense Microstructure ◽  
Mean Grain Size ◽  
The Mean

In this work, the colossal dielectric properties and Maxwell—Wagner relaxation of TiO2–rich Na1/2Y1/2Cu3Ti4+xO12 (x = 0–0.2) ceramics prepared by a solid-state reaction method are investigated. A single phase of Na1/2Y1/2Cu3Ti4O12 is achieved without the detection of any impurity phase. The highly dense microstructure is obtained, and the mean grain size is significantly reduced by a factor of 10 by increasing Ti molar ratio, resulting in an increased grain boundary density and hence grain boundary resistance (Rgb). The colossal permittivities of ε′ ~ 0.7–1.4 × 104 with slightly dependent on frequency in the frequency range of 102–106 Hz are obtained in the TiO2–rich Na1/2Y1/2Cu3Ti4+xO12 ceramics, while the dielectric loss tangent is reduced to tanδ ~ 0.016–0.020 at 1 kHz due to the increased Rgb. The semiconducting grain resistance (Rg) of the Na1/2Y1/2Cu3Ti4+xO12 ceramics increases with increasing x, corresponding to the decrease in Cu+/Cu2+ ratio. The nonlinear electrical properties of the TiO2–rich Na1/2Y1/2Cu3Ti4+xO12 ceramics can also be improved. The colossal dielectric and nonlinear electrical properties of the TiO2–rich Na1/2Y1/2Cu3Ti4+xO12 ceramics are explained by the Maxwell–Wagner relaxation model based on the formation of the Schottky barrier at the grain boundary.

INFLUENCE OF SAMARIUM SUBSTITUTION ON DIELECTRIC PROPERTIES OF BARIUM TITANATE BASED CERAMICS

2009 ◽  
Vol 23 (28) ◽  
pp. 3419-3425 ◽  
Author(s):  
PARVEEN KUMAR ◽  
SANGEETA SINGH ◽  
J. K. JUNEJA ◽  
CHANDRA PRAKASH ◽  
K. K. RAINA
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Barium Titanate ◽  
Curie Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Dielectric Behavior ◽  
Reaction Method ◽  
X Ray ◽  
Material Series

In this paper we report samarium substituted Ba 0.80 Pb 0.20 Ti 0.90 Zr 0.10 O 3 (BPZT) ceramics. The material series with compositional formula Ba 0.80-x Sm x Pb 0.20 Ti 0.90 Zr 0.10 O 3 with x varying from 0 to 0.01 in the steps of 0.0025 was chosen for investigations. The material was synthesized by solid state reaction method. Reacted powders compacted in the form of circular discs were sintered at 1325°C. All the samples were subjected to X-ray analysis and found to be single phase. Dielectric behavior was studied as a function of frequency and temperature and Curie temperature (Tc) was determined. Tc was found to decrease with increasing x. The details are discussed and presented here.

scholarly journals Effect on Magnetic Properties of Zinc Doped Nano Ferrites Synthesized by Precursor or Method

2013 ◽  
Vol 19 ◽  
pp. 37-43 ◽  
Author(s):  
T. Anjaneyulu ◽  
P. Narayana Murthy ◽  
S.M. Rafi ◽  
S. Bademiya ◽  
G. Samuel John
Keyword(s):  
Spinel Structure ◽  
Single Phase ◽  
Sem Analysis ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Zn Doping ◽  
Zn Ferrite ◽  
Phase Spinel ◽  
Ir Analysis ◽  
Zn Ions

Nanocrystalline Cu-Zn ferrites have been synthesized using precursor method. Cu-Zn ferrites were formed at low temperature without any impurities. The particle sizes were observed to decrease from 60 nm to 50 nm with increasing non-magnetic Zn doping. Cu is used to decrease the sintering temperature. The X-ray diffraction (XRD) and IR analysis of Cu-Zn revealed the formation of Single-Phase Spinel structure at very low annealing temperature. The particle sizes observed from XRD is very well in agreement with SEM analysis. Cu-Zn ferrite nanoparticles were observed to be dependent on the particle size. Saturation (Ms) and Remanence (Mr) magnetization of ferrites increases due to the modifications occurred among the A-B, A-A and B-B interactions of Spinel structure. The Coercive force (Hc) decreases with increase of Zn ions concentration.

Investigation of the in situ calcination of aerosol co-deposited NiO-Mn2O3 films

2019 ◽  
Vol 12 (03) ◽  
pp. 1950039 ◽  
Author(s):  
Michaela Schubert ◽  
Jaroslaw Kita ◽  
Christian Münch ◽  
Ralf Moos
Keyword(s):  
Crystal Structure ◽  
Electrical Properties ◽  
Spinel Structure ◽  
Single Phase ◽  
Electrical Measurements

An in situ calcination of an aerosol co-deposited (AcD) NiO-Mn2O3 film for the production of a single-phase cubic NiMn2O4 spinel film was investigated. Characterizations of the AcD film were performed before, during, and after calcination using SEM, XRD and electrical measurements. It could be shown that in situ calcination to mechanically stable films with single-phase cubic spinel structure is possible. Furthermore, changes in the crystal structure and the NTCR parameters [Formula: see text] and [Formula: see text] during calcination could be shown. After in situ calcination, the electrical properties are similar to those of conventional bulk ceramics.

AC Conductivity and Dielectric Properties of BiScO3–PbTiO3 Piezoelectric Ceramics

2021 ◽  
Vol 13 (9) ◽  
pp. 1807-1811
Author(s):  
Jae-Hoon Ji ◽  
Yoo-Young Oh ◽  
Bo Su Kim ◽  
Wook-Hee Han ◽  
Jung-Hyuk Koh
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Ac Conductivity ◽  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Ferroelectric Properties ◽  
Temperature Stability ◽  
Piezoelectric Ceramics ◽  
Dielectric Behavior ◽  
Wide Range

Bi-based BiMeO3 (where Me is a transition metal) has been extensively studied owing to its outstanding ferroelectric properties. The dielectric and electrical properties of piezoelectric ceramics can be enhanced by the addition of Bi-based materials such as BiAlO3, BiScO3 , and Bi(Mg, Ti)O3. Among them, BiScO3–PbTiO3 ceramics have shown excellent piezoelectric properties and temperature stability near the morphotropic phase boundary (MPB) region. Meanwhile, it is important to study the electrical properties of piezoelectric materials such as dielectric permittivity, conductivity of ferroelectric compounds, since dielectric and conductivities are related to pyroelectricity and piezoelectricity. In this study, the AC conductivity and dielectric properties of BiScO3–PbTiO3 ceramics were investigated with a wide range of frequencies and temperatures. Especially,the effect of PbTiO3 content on dielectric behavior of the BiScO3–PbTiO3 system was intensively studied by impedance spectroscopy.

Structural and Magnetic Properties of Different Temperature Sintering La-Substituted Barium Ferrite

2012 ◽  
Vol 583 ◽  
pp. 272-275
Author(s):  
Jie Li ◽  
Huai Wu Zhang ◽  
Yuan Xun Li ◽  
Qiang Li ◽  
Yan Bing Ma
Keyword(s):  
Magnetic Properties ◽  
Spinel Structure ◽  
Barium Ferrite ◽  
Single Phase ◽  
Sintering Temperature ◽  
Solid State Reaction Technique ◽  
Sem Images ◽  
Phase Spinel ◽  
Structural And Magnetic Properties ◽  
Microstructure Density

The Ba1-xLaxFe12O19 (0.0≤x≤0.6) ferrite materials were prepared by the standard solid state reaction technique method and sintered at 920 °C with 4 wt% Bi2O3 and at 1150 °C without Bi2O3 in air. The influence of La3+ contents on the microstructure, density, and magnetic properties were studied. The XRD results showed essentially single phase spinel structure. The SEM images of the samples had no obvious relationship with the substituting value. Saturation magnetization continuously decreased from 59.37 emu/g to 57.93 emu/g with sintering temperature from 1150 °C to 920 °C. However, coercive force reached the value of 4547.0 Oe when x=0.6 at 920 °C. The density of the samples also decreased monotonously with increasing x value.

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