Impedance spectroscopic studies in ferroelectric (Na1/2Bi1/2)TiO3

Saradhi, B. V. Bahuguna; Srinivas, K.; Prasad, G.; Suryanarayana, S. V.; Bhimasankaram, T.

doi:10.1016/s0921-5107(02)00576-7

Cited by 80 publications

(25 citation statements)

References 24 publications

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“…The semi circles at high frequency correspond to the bulk response of the grains of the sample as is commonly observed in other ceramics also [22][23][24].…”

Section: Resultsmentioning

confidence: 90%

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Impedance spectroscopy studies of K0.5Bi0.5TiO3

Rao¹,

Sankaram

2009

J Electroceram

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Lead free Potassium bismuth Titanate K 0.5 Bi 0.5 TiO 3 (KBT) was prepared by high temperature solid state reaction method in a closed crucible with excess KBT powder around the samples. A room temperature study of XRD confirms, single phase formation with tetragonal structure .Grain and grain boundary conduction is observed from complex impedance spectrum at high temperatures (425°C) by the appearance of two semicircular arcs. The Cole-Cole plots of impedance spectrum consisted of a Circular arc followed by a semicircular spur indicate that the dielectric phenomenon of KBT is due to conductive grain boundaries. The temperature variation of grain resistance and grain boundary resistance is observed with the activation energies. The presence of nonDebye type multiple relaxations has been confirmed by complex modulus analysis. The dielectric data obtained from impedance measurements, indicates broad dielectric peaks around 380°C. The ferroelectric nature confirmed from hysteresis plot. The DC Conductivity results indicate activation energy 0.54 eV below 400°C and 0.85 eV above 400°C. The AC conductivity values and electric modulus values are computed from the impedance data. The activation energies of AC conductivity have observed to decrease with decrease in frequencies.

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“…The semi circles at high frequency correspond to the bulk response of the grains of the sample as is commonly observed in other ceramics also [22][23][24].…”

Section: Resultsmentioning

confidence: 90%

“…NBT exhibits two structural phase transitions from ferroelectric rhombohedral to tetragonal (~200-350°C) and to paraelectric high temperature cubic phase (520-540°C) [4][5][6][7][8]. At about 320°C, NBT exhibits a broad maximum of electric permittivity.…”

Section: Introductionmentioning

confidence: 99%

Impedance spectroscopy studies of K0.5Bi0.5TiO3

Rao¹,

Sankaram

2009

J Electroceram

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“…In the present materials, the ac conductivity is found to increase with increase in frequency suggesting the bound carriers trapped in the sample. Conductivity varying at lower frequencies corresponds to space charge polarization [30]. Also, a change in slope has been observed at a particular frequency is related to ion hopping frequency [31][32][33].…”

Section: Conductivitymentioning

confidence: 99%

Ferroelectric Relaxor Behavior and Spectroscopic Properties of Ba<SUP>2+</SUP> and Zr<SUP>4+</SUP> Modified Sodium Bismuth Titanate

Tilak¹

2012

MATERIALS

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Polycrystalline ceramics (Na 0.5 Bi 0.5 ) 1-x Ba x Zr y Ti 1-y O 3, (BNBZT) (for x=0.10, 0.12; y=0.04), has been synthesized by conventional solid-state sintering. X-ray diffraction analysis indicates the formation of a single phase with tetragonal symmetry with pure perovskite structure. Scanning electron micrograph of the studied materials shows a distribution of grains. A broad dielectric peak with maximum permittivity has been observed near 1200 (for x=0.10, y=0.04) and 1600 (for x=0.12, y=0.04) respectively in the temperature range, RT-600℃. This result indicates that these materials may have great potential for a variety of high temperature applications. These ceramics show diffuse phase transition and the transition temperature shifting toward higher temperature with increasing frequency, which represents the relaxor behvaiour. The relaxor materials obey modified Curie-Weiss law and Vogel-Fulcher relationship. The values of the diffuseness parameter γ=2 for x = 0.10 and 1.67 for x = 0.12, obtained from the fit of a modified Curie-Weiss law established the relaxor type nature. For a more detailed interpretation of the ac data, the complex impedance (Z*) and electric modulus (M*) as a function of frequency f (i.e., 45 Hz-5 MHz) has been simultaneously analysed. Impedance study reveals that there exists a temperature dependent electrical relaxation phenomenon in the materials. Modulus represents hopping of ions and localized motion in studied compositions. Conductivity obey's Jonscher law

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“…A bajas temperaturas las especies de relajación son especies inmóviles como se indica por la caída monótona de Z´´ con la frecuencia lo que indica que predomina el efecto orientacional. 48 Las medidas de magnetización vs campo magnético fueron realizadas a temperatura ambiente (~298K) con un barrido entre -40 y 40 kOe, para todos los sistemas estudiados.…”

Section: Figura 3 Difractogramas De Los Polvos Cerámicos Del Sistemaunclassified

Modificación de las propiedades estructurales, eléctricas y magnéticas del BiFeO3 por la incorporación de Ba y Nb

Narváez¹,

Raigoza²,

Nieva³

2016

Quim. Nova

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.06 y 0.09) powders were synthesized using the citrate-gel method. Infrared spectroscopy indicated shifting of Bi/Ba-O and Fe/Nb-O bond vibrations and a structural transition was observed by X-ray diffraction. A Williamson-Hall (W-H) analysis revealed that Ba/Nb dopant reduces the particle size and increases the strain crystalline lattice. Impedance analysis suggests that electrical relaxation process is temperature dependent, for all compositions obtained. Furthermore, electrical conductivity increases with temperature showing a typical negative temperature coefficient of the resistance (NTCR) analogous to a semiconductor. Magnetization v magnetic field curves reveal weak ferromagnetic behaviour within the BiFeO 3 doped with Ba and Nb, and co-doped with Ba-Nb, measured at room temperature.Keywords: multiferroic; citrate-gel; W-H analysis; magnetic properties. INTRODUCCIÓNExisten muy pocos materiales multiferroicos tanto en su forma natural como sintetizados en un laboratorio, un material representativo de este grupo es la ferrita de bismuto, BiFeO 3 (BFO), que presenta ventajas sobre otros compuestos multiferroicos debido a sus elevadas temperaturas de Curie y de Néel (T C~ 1100 K, T N~ 640 K). El BFO ha despertado interés en las ciencias básicas y ha demostrado un gran potencial para nuevas aplicaciones, debido a que presenta propiedades ferromagnéticas (ordenamiento antiferromagnético tipo G) y ferroeléctricas a temperatura ambiente.1 El problema principal de este sistema es la dificultad de obtenerlo monofásico por métodos convencionales ya que al sintetizarlo se forman simultáneamente diversas fases secundarias como Bi 2 O 3 , Bi 2 Fe 4 O 9 y Bi 25 FeO 39 ; una de las opciones para eliminar la presencia de fases secundarias es su dopaje con cationes que sustituyan los sitios A y B en su estructura y a su vez, favorezca sus propiedades físicas. Un aumento de la magnetización fue reportado para cerámicas de BiFeO 3 dopadas, indicando una forma posible de suprimir la modulación de espines en soluciones sólidas Bi 1-x A x FeO 3 (A=La, Ba, Pb).2,3,4 Se encontró que el valor de la magnetización neta depende fuertemente de la clase de elemento diamagnético que se use como dopante; por ejemplo, la magnetización espontánea de las muestras dopadas con bario es al menos un orden de magnitud mayor que el observado para las soluciones sólidas resultado del dopaje con lantano con la misma concentración de dopante, 2,4 la naturaleza de una correlación entre el tipo de dopante diamagnético y las propiedades magnéticas de las muestras aún no es muy clara.3 Recientemente, algunos investigadores estudiaron la sustitución de hierro por niobio para el BFO, reportando un gran aumento en la resistividad eléctrica de las cerámicas obtenidas, una débil polarización remanente y un comportamiento similar al ferromagnético.5 Otros investigadores prepararon cerámi-cas de BFO sustituyendo el hierro por niobio y cobalto, reportando pequeñas transiciones de fase estructurales, así como bajas pérdidas dieléctricas, ellos sugieren que el do...

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Impedance spectroscopic studies in ferroelectric (Na1/2Bi1/2)TiO3

Cited by 80 publications

References 24 publications

Impedance spectroscopy studies of K0.5Bi0.5TiO3

Impedance spectroscopy studies of K0.5Bi0.5TiO3

Ferroelectric Relaxor Behavior and Spectroscopic Properties of Ba<SUP>2+</SUP> and Zr<SUP>4+</SUP> Modified Sodium Bismuth Titanate

Modificación de las propiedades estructurales, eléctricas y magnéticas del BiFeO3 por la incorporación de Ba y Nb

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