scholarly journals Technology and Electrophysical Properties of Multiferroic PZT–PFT Ceramics

2013 ◽  
Vol 58 (4) ◽  
pp. 1361-1364 ◽  
Author(s):  
P. Niemiec ◽  
R. Skulski ◽  
D. Bochenek ◽  
P. Wawrzała
Keyword(s):  
Dielectric Permittivity ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Hysteresis Loops ◽  
Wide Distribution ◽  
Ceramic Technology ◽  
Dielectric Losses ◽  
Dielectric Measurements ◽  
Ceramic Samples ◽  
The Mean

Abstract We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0.53Ti0.47O3)- x(PbFe0.5Ta0.5O3) [i.e. (1-x)PZT-xPFT] with x =0.25, 0.35 and 0.45 obtained using conventional ceramic technology. These materials belong to class of materials known as multiferroics. Solid solutions PZT-PFT are the lowest-loss room-temperature multiferroics known, and as a result there are very interesting for magnetoelectric devices. Paper presents the results of termogravimetric investigations, EDS, XRD and main dielectric measurements. It has been stated that with increasing content of PFT decreases the mean diameter of grains and more wide distribution of grain diameters is observed. For x =0.25 sharp phase transition from ferroelectric phase to paraelectric one is observed and high values of dielectric permittivity. Composition PZT-PFT with x =0.45 has the lowest values of dielectric permittivity, and the transition is more diffused. The increase of x leads also to the shift of the temperature of maximum of dielectric permittivity towards lower temperatures. Samples with x =0.25 and x =0.35 exhibit very low values of dielectric losses up to about 100°C. Dielectric losses for samples with x =0.45 are higher. For obtained PZT-PFT samples we have investigated P-E hysteresis loops at room temperature for frequency 1 Hz. For composition x =0.25 it after application the field about 2.5 kV/mm polarization is equal approximately 28 μC/cm2, while for x =0.35, and x =0.45 after application the field about 2.0 kV/mm the polarizations are equal about 25 μC/cm2 and 20 μC/cm2 respectively. Very low values of losses and high values of polarization lead to the conclusion that interesting material PZT-PFT for applications should be composition with x =0.25.

Technology and Properties of (1-x)PZT-(x)PFW Ceramics with 0.25

2014 ◽  
Vol 605 ◽  
pp. 424-427 ◽  
Author(s):  
Ryszard Skulski ◽  
Ewa Nogas-Cwikiel ◽  
Dariusz Bochenek ◽  
Przemysław Niemiec ◽  
Paweł Wawrzała
Keyword(s):  
Solid Solution ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Ceramic Technology ◽  
Ceramic Samples

We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0.53Ti0.47O3)-x (PbFe2/3W1/3O3) [i.e. (1-x)PZT-xPFW] with x = 0.25, 0.35, 0.45 and 0.55 obtained from oxides using conventional ceramic technology. In this paper we present the results of investigations of XRD and main dielectric properties. For x = 0.25 and x = 0.35 we investigated also P-E hysteresis loops at room temperature.

scholarly journals Особенности структуры и диэлектрических свойств керамик на основе титаната натрия-висмута

2018 ◽  
Vol 60 (3) ◽  
pp. 426
Author(s):  
Е.Д. Политова ◽  
Н.В. Голубко ◽  
Г.М. Калева ◽  
А.В. Мосунов ◽  
Н.В. Садовская ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Relative Dielectric Permittivity ◽  
Dielectric Losses ◽  
Relaxor Behavior ◽  
Temperature Dependences ◽  
Ferroelectric Phase Transitions ◽  
Formation Specific

AbstractThe phase formation, specific features, and the dielectric properties of the ceramics of compositions from the region of morphotropic interface in the (Na_0.5Bi_0.5)TiO_3–BaTiO_3 system modified by Bi(Mg_0.5Ti_0.5)O_3 and also low-melting additions KCl, NaCl–LiF, CuO, and MnO_2 that favor the control of the stoichiometry and the properties of the ceramics have been studied. The ceramics are characterized by ferroelectric phase transitions that are observed as jumps at temperatures near 400 K and maxima at T _m ~ 600 K in the temperature dependences of the dielectric permittivity. The phase transitions at ~400 K demonstrate the relaxor behavior indicating the existence of polar domains in the nonpolar matrix. An increase in the content of Bi(Mg_0.5Ti_0.5)O_3 favor a decrease in the electrical conductivity and dielectric losses of the samples, and the relative dielectric permittivity at room temperature ε_rt is retained quite high, achieving the highest values ε_rt = 1080–1350 in the ceramics modified with KCl.

scholarly journals The Properties of (Pb0.97Ba0.03)[(Zr0.98Ti0.02)1-zSnz]O3 Ceramics with 0 < z < 0.08

2013 ◽  
Vol 58 (4) ◽  
pp. 1377-1380
Author(s):  
D. Brzezińska ◽  
R. Skulski ◽  
P. Wawrzała ◽  
G. Dercz
Keyword(s):  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Barium Carbonate ◽  
Hysteresis Loops ◽  
Ceramic Technology ◽  
Dielectric Measurements ◽  
Ceramic Samples

Abstract We present the results of obtaining and investigations of (Pb1-x Bax )((Zr1-yTiy) 1-zSnz )O3 (PBZTS) ceramics with x =const =0.03, y =const=0.02, z =0, 0.02, 0.04, 0.06 and 0.08. Investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. Ceramic samples have been obtained by conventional ceramic technology from oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The calcined powders were crushed and next pressed into discs and sintered free sintering (FS) method. For such obtained samples the following investigations have been done: EDS, XRD, microstructure of fractured samples, dielectric measurements, /’-/^hysteresis loops investigations at various temperatures.

Electrical and Magnetic Properties of Mg-Cr and Co-Cr Nano Ferrites Synthesized by Citrate-Gel Method

2015 ◽  
Vol 241 ◽  
pp. 69-92 ◽  
Author(s):  
M. Raghasudha ◽  
D. Ravinder ◽  
P. Veerasomaiah
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
High Frequency ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Dielectric Measurements ◽  
Electrical And Magnetic Properties ◽  
Potential Applications

The work deals with the study of electrical and magnetic properties of Magnesium-Chromium and Cobalt-Chromium nanoFerrites for their potential applications synthesized by Citrate-Gel auto-combustion method. Structural Characterization of prepared nanoferrites was performed using XRD, SEM, EDS and TEM. XRD patterns confirmed the formation of homogeneous single phased cubic spinel belonging to the space group Fd3m (in agreement with ICSD Ref. data). It is found that crystallite size of Mg-Cr ferrites was in the range of 7-23nm and that of Co-Cr nanoferrites in the range of 6-12 nm. Structural morphology of both the ferrites was studied by SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy). Elemental compositional analysis was carried out by EDS.Electrical properties such as D.C. resistivity of prepared Mg-Cr and Co-Cr nanoferrites were studied by two probe method. The dielectric measurements as a function of frequency at room temperature were performed in the frequency range of 20Hz to 2MHz using LCR meter. Various dielectric parameters like dielectric constant (ε′), dielectric loss (ε′′) and dielectric loss tangent (tan δ) were measured as a function of frequency. The magnetization measurements of the prepared nanoferrite samples were carried out at room temperature in the applied field of ±15KOe using Vibrating Sample Magnetometer (VSM). From the obtained M-H loops, various magnetic parameters such as Saturation Magnetization (Ms), Coercivity (Hc) and Remanence Magnetization (Mr) were measured. Magnetization as a function of field (±10T) at 5K, 25K, 300K temperatures was measured using VSM. Super-paramagnetic nature of some specified samples in Mg-Cr nanoferrites system was investigated from the temperature dependence of both the field cooled (FC) and the zero-field cooled (ZFC) magnetization measurements under a field of 100 Oe in the temperature range 5K to 350K.From the results of D.C. resistivity measurements it is observed that the resistivity decreases with increase in temperature for both Mg-Cr and Co-Cr nanoferrites suggesting the semiconducting behavior of the samples. Dielectric measurements suggest that the conduction in the ferrite systems may be due to the polaron hopping mechanism. The low loss tangent values at high frequency show the potential applications of these materials in high frequency microwave devices. Mg-Cr nanoferrites were synthesized yielding narrow hysteresis loops which are the characteristic of very soft magnetic materials that are desirable for their utility in Transformers, Inductor cores, Microwave devices and Magnetic shielding. Hysteresis loops of Co-Cr nanoferrites show the medium hard magnetic behavior of the materials. MgFe2O4 shows superparamagnetic behavior above room temperature and MgCr0.9Fe1.1O4 shows superparamagnetic behavior with the blocking temperature 94.5K. Hence these nanoferrites find applications in targeted drug delivery and in Magnetic Resonance Imaging (MRI) in biomedical field. The observed results can be explained in detail on the basis of composition and crystallite size.Contents of Paper

scholarly journals Technology, Physical Properties and Phase Transitions in PMN-PT-PS Ceramics

2011 ◽  
Vol 56 (4) ◽  
pp. 1051-1056 ◽  
Author(s):  
R. Skulski ◽  
D. Bochenek ◽  
P. Wawrzała
Keyword(s):  
Solid Solution ◽  
Phase Transitions ◽  
Dielectric Permittivity ◽  
Physical Properties ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ceramic Samples

Technology, Physical Properties and Phase Transitions in PMN-PT-PS CeramicsSolid solution of (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPbSnO3(PMN-PT-PS) investigated in this paper is based on (1-x)PMN-xPT (PMN-PT) where, with increasingx, the transition from relaxor to ferroelectric properties is observed depending on composition. PMN-PT ceramics with 0.25<x<0.4 has been obtained using sol-gel method and next mixed together with PS ceramics obtained from oxides. Final sintering of ceramic samples was pressureless. We present the results of microstructure and XRD investigations, dielectric permittivity and hysteresis loops measurements vs. temperature.

scholarly journals Effect of Cu Doping on Structural and Dielectric Properties of Pb1-xCux(Zr0.52Ti0.48)O3(PCxZT) (0 ≤ x ≤ 0.2) Ceramics Prepared by Sol-Gel Method

2021 ◽  
Vol 33 (3) ◽  
pp. 665-670
Author(s):  
M. Ahabboud ◽  
T. Lamcharfi ◽  
F. Abdi ◽  
N. Hadi ◽  
F.Z. Ajyaje ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Cu Doping ◽  
X Ray ◽  
Different Temperatures

In present work, the structural and dielectric properties of Pb1-xCuxZr0.52Ti0.48O3 (PCxZT) ceramics where x = 0. 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 were studied. Powder of the compositions (PCxZT) was obtained by sol-gel route, the powders were calcined at 700 ºC for 4 h and sintered at 1100 ºC for 4 h. X-ray diffraction analysis and Raman spectroscopy suggest the formation of mixed-phase of tetragonal and rhombohedral structure which was confirmed by Rietveld refinement. Dielectric measurements of the compounds were studied as a function of temperature (from room temperature to 420 ºC at different frequencies) and as a function of frequency (from 100 Hz to 2 MHz at different temperatures). The temperature variation of the real permittivity gives evidence of the ferroelectric phase transition as well as of the resonance behaviour also observed in the dielectric permittivity frequency-dependent variation.

scholarly journals Mагнитные и диэлектрические свойства мультиферроиков (1-x)BiFeO-=SUB=-3-=/SUB=--xYMnO-=SUB=-3-=/SUB=-

2019 ◽  
Vol 45 (7) ◽  
pp. 21
Author(s):  
В.И. Михайлов ◽  
В.Т. Довгий ◽  
А.И. Линник ◽  
З.Ф. Кравченко ◽  
В.И. Каменев ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Magnetic Fields ◽  
Solid Solutions ◽  
Coercive Field ◽  
Hysteresis Loops ◽  
Ferromagnetic Materials ◽  
Ceramic Samples ◽  
Weak Magnetic Fields ◽  
Soft Ferromagnetic

AbstractMagnetic hysteresis loops obtained in the fields from 0 to ±2.5 kOe and dielectric permittivity ε (at 1 kHz, 1 MHz, and 8.3 GHz) of (1 – x )BiFeO_3– x YMnO_3 composite multiferroics (0 ≤ x ≤ 0.5) were studied. Ceramic samples of solid solutions were made by the nitrate process. Compositions (1 – x )BiFeO_3– x YMnO_3 with 0.1 ≤ x ≤ 0.5 were found to be soft ferromagnetic materials sensitive to weak magnetic fields. Coercive field H _ c is about 20–32 Oe for these samples. The maximal magnetization was observed in the sample having x = 0.35. For the samples with 0 ≤ x ≤ 0.4 at T = 300 K, the permittivity was ε ~ 17.6–248.6 at the frequency of 1 kHz, 7.8–63.2 at 1 MHz, and 4 ± 0.3 at 8.3 GHz.

The Determination of the Magnetoelectric Coupling Coefficient in Ferroelectric–Ferromagnetic Composite Based on PZT–Ferrite

2013 ◽  
Vol 58 (4) ◽  
pp. 1401-1403 ◽  
Author(s):  
J.A. Bartkowska ◽  
R. Zachariasz ◽  
D. Bochenek ◽  
J. Ilczuk
Keyword(s):  
Dielectric Permittivity ◽  
Coupling Coefficient ◽  
Mean Field ◽  
Field Approximation ◽  
Theoretical Description ◽  
Magnetoelectric Coupling ◽  
Mean Field Approximation ◽  
Dielectric Measurements ◽  
Temperature Dependences ◽  
Multiferroic Composite

Abstract In the present work, the magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the multiferroic composite was determined. The research material was ferroelectric-ferromagnetic composite on the based PZT and ferrite. We investigated the temperature dependences of the dielectric permittivity (") for the different frequency of measurement’s field. From the dielectric measurements we determined the temperature of phase transition from ferroelectric to paraelectric phase. For the theoretical description of the temperature dependence of the dielectric constant, the Hamiltonian of Alcantara, Gehring and Janssen was used. To investigate the dielectric properties of the multiferroic composite this Hamiltonian was expressed under the mean-field approximation. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified.

scholarly journals The Atmosphere of the Underground Electric Railways of London: A Study of its Bacterial Content in 1920

1923 ◽  
Vol 22 (2) ◽  
pp. 123-155 ◽  
Author(s):  
J. Graham Forbes
Keyword(s):  
Body Temperature ◽  
Room Temperature ◽  
The Mean ◽  
Bacterial Content ◽  
The City

1. The bacterial content of the air of the Underground Railways, when the average of all results of the bacteriological investigations is taken, does not numerically compare unfavourably with the outside air of London.2. The ratio of the number of organisms growing at room temperature appears to be about 14 for railway air to 10 outside air. For those growing at body temperature the ratio is considerably higher, namely 2 to 1 respectively. The mean per litre, for room temperature organisms, is about 9 in railway air, 6·3 in the outside air; for body temperature organisms 4·6 for railway air, 2·2 for outside air.3. The bacterial content of platform air, except on the City and South London Railway, would appear to be higher than that of carriage air; the total mean for platform air being 52 and for carriage air 42·8 organisms per 5 litres, or a ratio of 16·4 and 13·5 respectively to 10 of the open air. The higher proportion in platform air is generally speaking to be accounted for by the greater amount of draught and dust disturbance.4. The ratios of the total bacterial content of railway carriage air and carriage and platform air on the six lines to open air are estimated in the following proportions:

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