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1

AC-conductivity of polycrystalline Ba(Ti0.90Zr0.10)O3

Kajtoch Cz.

Inżynieria Materiałowa

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2011

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Vol. 32, nr 1

37-39

EN

Dielectric spectroscopy was applied in order to measure the complex dielectric permittivity and the electric AC-conductivity of ferroelectric Ba(Ti0.90Zr0.10)O3 (BTZ10). It was affirmed, that 10% substitution of Zr ions changed the type of a phase transition. This transition has strongly diffusive nature. The temperature Tm (temperature of the maximum electric permittivity ??) was not dependent on frequency of the electric measuring field. At this temperature maxima of AC-conductivity values were observed. These maxima were strongly dependent on the frequency of the applied electric field. The small values of the phase angle in a broad temperature region confirm polar character of BTZ10 material. It is connected with the occurrence of polar regions (clusters). BTZ10 can bee used as a material with the positive temperature resistance coefficient (PTRC).

PL

Metoda spektroskopii dielektrycznej została zastosowana do pomiarów zespolonej przenikalności elektrycznej i przemiennoprądowego przewodnictwa elektrycznego ferroelektrycznego polikryształu Ba(Ti0,90Zr0,10)O3 (BTZ10). Stwierdzono, że 10% podstawienie jonów Zr zmienia typ przemiany fazowej. Przemiana staje się silnie rozmyta. Temperatura Tm (temperatura maksimum przenikalności elektrycznej ??) nie zależy od częstotliwości elektrycznego pola pomiarowego. W tej samej temperaturze obserwuje się maksimum wartości przemiennoprądowego przewodnictwa elektrycznego. Wartość tego maksimum silnie zależy od częstotliwości przyłożonego pola elektrycznego. Małe wartości kąta fazowego w szerokim przedziale temperatury świadczą o polarnym charakterze materiału. Jest to związane z występowaniem polarnych obszarów (klastrów). BTZ10 może być wykorzystany jako materiał z dodatnim temperaturowym współczynnikiem rezystancji (PTRC).

2

Technology, physical properties and phase transitions in PMN-PT-PS ceramics

Skulski R., Bochenek D., Wawrzała P.

Archives of Metallurgy and Materials

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2011

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Vol. 56, iss. 4

1051-1056

EN

Solid 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 increasing x, 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.

PL

Opisany w tej pracy roztwór stały (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3]-yPbSnO3 (PMN-PT-PS) jest oparty na roztworze (1-x)PMN-xPT (PMN-PT) w którym, w zależności od składu ma miejsce przejście od właściwości relaksorowych do ferroelektrycznych ze wzrastającym x. Ceramika PMN-PT z 0,25< x <0,4 została otrzymana metodą zolowo-żelowa, a następnie wymieszana z ceramika PS otrzymana z tlenków. Końcowe spiekanie było spiekaniem swobodnym. Przedstawiamy rezultaty badań mikrostruktury, badań rentgenowskich, zależności przenikalności dielektrycznej i pętli histerezy dielektrycznej od temperatury.

3

Dielectric spectroscopy study of Ba0.98Na0.02Ti0.98Nb0.02O3 ceramic

Bąk W., Gabryś M., Kajtoch C., Stanuch K., Starzyk F.

Archives of Materials Science and Engineering

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2009

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Vol. 39, nr 2

107-110

EN

Purpose: The purpose of this work was to investigate dielectric properties of new ceramic solid solution Ba0.98Na0.02Ti0.98Nb0.02O3 (BNTN2) within the temperature range 153 K - 473 K. Design/methodology/approach: The dielectric spectroscopy method was applied to measure frequency and temperature dependence of complex dielectric permittivity, complex admittance, phase angle. The frequency dependence of ac conductivity at constant temperature was analysed as well as reciprocal permittivity and dielectric modulus as functions of temperature and frequency were compared. The Curie-Weiss rule and its generalized formula were applied in outcomes analysis. Findings: The ferroelectric - paraelectric (FE - PE) phase transition occurring in BNTN2 was found as having diffusive nature. In the paraelectric phase at about 400 K the diffusivity of transition step is correlated with the same kind of transition in BaTiO3 (BT) (transition of FE - PE type) and with structural transition occurring in NaNbO3 (NN). Within the temperature range below Tm = 308 K, dependences of dielectric properties of BNTN2 ceramic on temperature and frequency was found as having relaxor type of behaviour. Research limitations/implications: The confirmations of achieved findings will be possible by more precise BNTN2 structure determination by means X-ray diffraction. Also closer explanation of FE - PE phase transition can be performed by dielectric measurements within broader frequency range up to 1.8 GHz ( diffusive versus relaxor character of transition). Originality/value: The new solid solution of BNTN2 was prepared. The structure of this material was characterized as dielectrically active and having FE - PE phase transition which was described.

4

Dielectric properties of polycrystalline (Ba0.40Sr0.60)O3

Kajtoch C., Bąk W., Gabryś M., Mroczka K., Starzyk F., Żmija J.

Archives of Materials Science and Engineering

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2009

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Vol. 40, nr 1

33-36

EN

Purpose: Purpose of this paper is to qualify of the degree and the causes of broadening of the phase transition in the polycrystalline solid solution (Ba0.40Sr0.60)TiO3 (BS60T). Design/methodology/approach: Polycrystalline samples of (Ba0.40Sr0.60)TiO3 (BS60T) were prepared by calcinations method at temperature 1570K. Images of the morphology of the samples were taken by means of electron microscope Philips SEM 525M at room temperature. Dielectric measurements were performed with application of Quatro Cryosystem 4.0 Agilent Precision LRC meter HP4824A equipped with WinDETA 5.62 software Novocontrol. Measurements were taken under cooling with 2K/min speed. Measuring electric field frequency was from the range 20 Hz - 1 MHz. Findings: The dielectrometry was applied to measure complex dielectric permittivity and other dielectric functions of ferroelectric (BS60T). It was affirmed, that 60% substitution of Sr ions changed the type of phase transition. Weak dependence of temperature Tm=208 K (temperature of maximum electric permittivity &epsilon') on frequency of the external electric field testifies about diffused character of the phase transition (DPT). The polar character of this material was also observed in the paraelectric phase (to 360 K). This observation is connected with the occurrence of polar clusters in this phase. Research limitations/implications: Results can be used in order to describe the phase transition modifications in the solid solutions with ferroactive substitutions in sublattice B of the perovskite. Originality/value: Value of this work relies on the experimental examination of the electric properties of BS60T solid solution. The low value of phase angle in the paraelectric phase is connected with the occurrence of the polar regions (clusters).

5

Characteristics of phase transitions in Ba0.995Na0.005Ti0.995Nb0.005O3 ceramic

Bąk W.

Archives of Materials Science and Engineering

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2009

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Vol. 39, nr 2

75-79

EN

Purpose: The purpose of this work was to prepare ceramic material BaTiO3 (BT) as well as solid solution of Ba1-xNaxTi1-xNbxO3 (for x = 0.005) (BNTN05) type and correlate their structural (polycrystalline) properties with phase transitions within the temperature range from 153 K to 473 K. Design/methodology/approach: The dielectric spectroscopy method has been applied to measure dielectric and electric parameters within the frequency from 20 Hz to 1 MHz. Findings: The measured dependences of: complex dielectric permittivity and its phase angle (between measuring voltage and current response) points out on complex phase transition character for both investigated materials. Experimental outcomes for BT are consistent with those already published. Achieved results in the case of BNTN05 are published here for the first time. They were correlated with those of BT as unmodified one. Phase transitions parameters of both materials were described by means of generalised Curie-Weiss rule including step of phase transition diffusivity. Small amount (x = 0.005) of NaNbO3 (NN) admixture makes sharp, classical transition of first order kind occurring in the case of BT, to be a diffusive one and shifted by about 20 K towards lower temperatures. Research limitations/implications: Further investigations should be carried out in a broaden frequency range (up to 1.8 GHz) in order to establish the influence of network dynamics on ferroelectric-paraelectric phase transition as well as others low-temperature phase transitions. In order to complete structural data of new BNTN05 material additional X-ray and calorimetric measurements will be performed. Originality/value: The same method and components were used for preparation of BT and new BNTN05 material. Thermally induced phase transitions, mutually related in both materials were measured and described.

6

Determination of chemical composition of (Pb,La)(Zr,Ti)O3 type ferroelectric ceramics by WD-XRF and ED-EPMA

Sitko R., Zawisza B., Płońska M., Malicka E.

Chemia Analityczna

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2008

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Vol. 53, No. 1

123-131

EN

The stoichiometry determination of lanthanum doped lead zirconate titanate (PLZT) by the wavelength-dispersive X-ray fluorescence spectrometry (WD-XRF) and energy-dis-persive-electron-probe microanalysis (ED-EPMA) is presented. For WD-XRF measurements the analyzed materia! was mixed with boric acid in the ratio 1:20 and pressed into pellets. The multielement standard samples were prepared by mixing appropriate amounts of analyte oxides (PbO, TiO2, ZrO2 and La2O3,) with boric acid. The obtained results were compared with the analysis of PLZT performed by ED-EPMA. The matrix effects were corrected using threoretical influence algorithm for intermediate-thickness samples (WD-XRF) and ZAP method (ED-EPMA).

PL

Przedstawiono metodę oznaczania stechiometrii tytanianu i cyrkonianu ołowiu domieszkowanego lantanem (PLZT) z wykorzystaniem rentgenowskiej spektrometrii fluorescencyjnej z dyspersją długości fali (WD-XRF) i mikroanal izy rentgenowskiej zdyspersjąenergii (ED-EPMA). Do pomiarów WD-XRF analizowany materiał był mieszany z kwasem borowym w stosunku l :20 i prasowany w pastylkę. Wielopierwiastkowe próbki wzorcowe były przygotowane przez zmieszanie odpowiednich ilości tlenków analitów (PbO, TiO2ZrO2 i La2O3) z kwasem borowym. Uzyskane rezultaty porównano z wynikami ED-EPMA. Efekty matrycy korygowano za pomocą algorytmu teoretycznych współczynników wpływów dla próbek o grubości pośredniej (WD-XRF) oraz metodą ZAF (ED-EPMA).

7

Dielectric properties of polycrystalline (Ba0.60Sr).40)Ti0.8O3

Gabryś M.

Archives of Materials Science and Engineering

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2008

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Vol. 34, nr 1

27-30

EN

Purpose: The purpose of the work was to determinate the influence of the ferroactive Sr substitutions in sublattice A and the nonstoichiometry in sublattice B on changes of physical properties and the character of phase transition (PT) in pure barium titanate BaTiO3 (BT). Design/methodology/approach: The polycrystalline samples of (Ba0.60Sr0.40)TiO3 and (Ba0.60Sr0.40)Ti0.8O3 were obtained by the calcinations method in temperature 1620 K. The dielectric measurements were executed by automatic device (QUATRO KRIO 4.0 with LCR Agilent 4824A meter and BDS 1100 cryostat). The materials were investigated under cooling conditions with speed of 2 K/min and within frequency range from 20 Hz to 1 MHz. Findings: The dielectrometry was applied to measure complex dielectric permittivity and other dielectric functions of ferroelectric (Ba0.60Sr0.40)TiO3 (BST-40) and (Ba0.60Sr0.40)Ti0.8O3 (BST-40/0.8). It was affirmed, that 40% substitution of Sr ions as well as 20% deficiency of Ti ions in solid solution reduced temperature and changed the type of phase transformation. The transformation stood strongly diffused. The weak dependence of temperature Tm (peak of electric permittivity ε') from frequency of electric measuring field was observed. It means, that this material should be prescribed to the class of ferroelectrics with diffused phase transformation (DPT). The polar character of this solution was also observed in the paraelectric phase. It is connected with the occurrence of polar clusters in paraelectric phase. Practical implications: Results can be used to construct the model describing changes in the solid solutions with ferroactive and nonferroactive substitutions in sublattice A or B of the perovskite. Originality/value: Value of this work relies on the experimental examination of the electric properties of nonstoichiometric BST-40 solid solution. The low value of phase angle in the paraelectric phase was connected with the occurrence of the polar regions.

8

Ferroic smart materials

Surowiak Z., Bochenek D., Korzekwa J.

Electronics and Telecommunications Quarterly

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2007

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Vol. 53, No 2

193-219

EN

Thes paper presents the general properties of ferroic materials (crystals, ceramics). Ferroics is the general term covering ferromagnetic materials (FM), ferroelectric materials (FE) and ferroelastic materials (FES). Those three groups of materials are called "simple primary ferroics". Ferroelasticity is the mechanical or elastic analogue for ferromagnetism and ferroelectricity. The materials which exhibit both ferroelectric (FE) and ferroelastic (FES) properties are described as ferroelastoelectrics (FE+FES=FESE). The ferroics (FM, FE, FES) and ferroelastoelectrics (FE+FES) belong to smart family materials. They are defined as materials which have some properties that can be altered and controlled by external stimuli (magnetic, electric, mechanical, thermal). Smart materials can be used in many technology fields such as automation, control process, robotics, material processing, aerospace engineering, automotive and electronic industry, defense technology, medical technology and biotechnology.

9

Study of domain structure in (211)-cut (Pb(Mg1/3nb2/3)O3)0:7(Pbtio3)0:3 single crystal by temperature-dependent piezoresponse force microscopy

Wong K. S., Dai J. Y., Jia Y. M., Zhao X., Luo H. S.

Archives of Metallurgy and Materials

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2007

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Vol. 52, iss. 1

13-17

EN

PMN-xPT is relaxor ferroelectrics with great potential in the application of novel devices. At the morphotropic phase boundary with x ∼28%-36% of PT, PMN-xPT exhibits complex crystal structure and phase transformation, which are not fully understood yet. The ferroelectric domain evolution study may reveal the mechanism of phase transformations induced by temperature or electrical field. In this work, we report the study of domain evolution of pmn-30% PT single crystal by means of temperature-dependent piezoresponse force microscopy (PFM) and electrical measurement. Observation of poled (211)-cut sample under reveal that lamellar domains are developed after poling. During temperature increase, the lamellar domains become smaller, and the phase transformation from rhombohedral-orthorhombic/monoclinic-tetragonal phase is progressing according to polarization rotation. When temperature is higher than Tm, the domain contrast becomes very weak and finally disappears. After heating and cooling cycle, the polar nonosized regions and speckle-shaped microdomains with random arrangement can be observed in the PFM image.

PL

PMN-xPT jest ferroelektrykiem posiadającym duże potencjalne możliwości zastosowań w nowoczesnych urządzeniach. Na morfotropowej granicy fazowej zawierającej z ∼28%-36% PT, MPT-xPT wykazuje złożoną strukturę krystaliczną i przemianę fazowa, która nie była dotychczas wyjaśniona. Badanie zmian zachodzących w domenach ferroelektrycznych może wyjaśnić mechanizm przemian fazowych wywołanych temperaturą lub polem elektrycznym. W pracy przedstawiamy badania zmian domen monokryształu PMN-30% PT przy użyciu mikroskopii sił z czujnikiem piezoelektrycznym przy zmiennej temperaturze (PFM) oraz pomiarów elektrycznych. Obserwacje ukierunkowanej próbki o przekroju (211) wykazały, że płytkowe domeny powstają z niestabilnej struktury pojedynczych domen na skutek biegunowości. PFM w zmiennej temperaturze dla próbki biegunowej ujawnił zmiany domen. Wraz ze wzrostem temperatury płytkowe domeny rosną i następuje przemiana fazowa z fazy romboedrycznej-ortorombowej lub jednoskosnej-tetragonalnej zgodnie z rotacją polaryzacji. Gdy temperatura jest wyższa niż Tm kontrast domenowy staje się bardzo słaby i ostatecznie zanika. Po cyklu wygrzewania i chłodzenia obserwowano na Obrazach PFM PNRs i chaotycznie rozłożone mikrodomeny o kształcie cętek.

10

Mechanizmy rozpraszania światła w elektrooptycznej ceramice PLZT

Surowiak Z., Płońska M.

Kwartalnik Elektroniki i Telekomunikacji

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2005

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Vol. 51, z. 1

84--104

PL

Ważną rolę w budowie elementów i urządzeń optoelektronicznych od wielu lat odgrywa przezroczysta ceramika ferroelektryczna. Otrzymanie takiej ceramiki stanowi trudny i złożony proces technologiczny, gdyż występuje w niej wiele centrów rozpraszania i absorpcji światła, które to zjawiska decydują o przezroczystości materiałów optycznych. Znajomość mechanizmów fizycznych procesów rozpraszania i absorpcji światła jest podstawowym warunkiem powodzenia w projektowaniu i otrzymywaniu elektrooptycznej ceramiki ferroelektrycznej. W ceramice ferroelektrycznej obok rozpraszania Rayleigha, Brillouina i Ramana wystąpić może rozpraszanie światła uwarunkowane również innymi czynnikami, w tym ścianami domenowymi. Sklasyfikowano i przeanalizowano te czynniki w funkcji długości fali świetlnej, grubości płytki ceramicznej, rozmiarów ziarn i stanu spolaryzowania ceramiki. Przedstawione rezultaty dotyczą przezroczystej ceramiki PLZT oraz ceramiki PZT domieszkowanej bizmutem. Praca ma charakter przeglądowy i stanowi podsumowanie badań procesów rozpraszania światła laserowego w ferroelektrycznej ceramice optycznej.

EN

For many years the transparent ferroelectric ceramics has played the important role in construction of optoelectronic elements and devices. Fabrication of such ceramics is determined by difficult and complex technological process. Many centres of the light scattering and absorption, decide about transparency of the optical materials. The understanding of physical mechanisms of the light scattering and absorption processes is the basic condition of success in designing and obtaining of ferroelectric electrooptic ceramics. Beside of the Rayleigh, Brillouin and Raman scattering processes the light scattering in ferroelectric ceramics is conditioned also by different factors e.g. by the presence of the domain walls. These factors have been classified and analysed according to the light wavelength, thickness of the ceramic plate, the grain sizes and state of ceramics after polarization. Four main mechanisms of the light scattering are possible in the optical ferroelectric ceramics (they are conditioned by microstructure and domain structure): (1) the light scattering on the crystallites boundaries conditioned by ceramic admixtures, as well as structural and stoichiometric (chemical) heterogeneity; (2) the light scattering on the crystallite boundaries of ferroelectric ceramics, connected with a discreteness of the refractive index; (3) the Rayleigh light scattering on the 180° domain walls; (4) the light scattering conditioned by the domain walls with diversifield internal stress. The present paper introduces results on transparent PLZT ceramics as well as bismuth doped PZT ceramics. It has a review character and summarizes of investigations of processes of the laser light scattering in ferroelectric optical ceramics.

11

XRF microanalysis of Pb(ZrxTi1-x)O3 type nanocrystalline ferroelectric powders by thin layer method

Jurczyk J., Zawisza B., Sitko R., Buhl F., Osińska K., Płońska M.

Chemia Analityczna

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2002

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Vol. 47, No. 6

925-934

EN

A method of wavedispersive XRF analysis of Pb(Zr(x)Ti(1-x))O3 type nanocrystalline ferroelec tric powders (PZT) has been presented. Matrix effects have been minimized by using the thin layer method. Preparation of the nature sample has consisted in digesting 25 mg of the materials in hydrochloric acid and 30% hydrogen peroxide (1 +1), diluting up to 25 mL, and placing 0.5 mL of the obtained solution on a substrate. Standard samples of the same chemical composition but varied masses have been prepared to simplify calibration. Determined elements in nature samples occur within the following concentration ranges: Pb from 66.72% to 69.84%, Zr from 8.54% to 14.04%, and Ti from 3.68% to 9.16%. The detection limits for 0.5 mg samples were obtained: Pb = 1.1 x 10(-3) mg (0.22%), Zr= 1.3 x 10(-3) mg (0.26%), Ti = 2.3 x 10(-4) mg (0.05%).

PL

Opracowano metodę mikroanalizy XRF nanokrystalicznych proszków ferroelektrycznych typu Pb(Zr(x)Ti(1-x))O(3) (PZT). W celu wyeliminowania efektów matrycy zastosowano technikę cienkiej warstwy. Przygotowanie próbek naturalnych do analizy sprowadza się do roztworzenia 25 mg badanego materiału w kwasie chlorowodorowym i 30% nadtlenku wodoru (1 + 1), rozcieńczeniu do objętości 25 mL i nakropleniu 0.5 mL uzyskanego roztworu na podłoże. Do kalibracji wykorzystano wielopierwiastkowe wzorce syntetyczne o tym samym składzie jakościowym lecz różnych masach. Oznaczane pierwiastki występowały w zakresach stężeń: Pb od 66.72% do 69.84%, Zr od 8.54% do 14.04% i Ti od 3.68% do 9.16%. Granice wykrywalności dla 0.5 mg próbki wynoszą: Pb = 1.1 x 10(-3) mg (0.22%), Zr = 1.3 x 10(-3) mg (0.26%), Ti = 2.3 x 10(-4) mg (0.05%).