Influence of vanadium on electrical and microstructural properties of CaCu3Ti4O12/CaTiO3

Ramajo, Leandro Alfredo; Parra, Rodrigo; Varela, José Arana; Reboredo, María Marta; Ramírez, M. A.; Castro, M. S.

doi:10.1016/j.jallcom.2010.03.064

Cited by 37 publications

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“…The static dielectric constant of CCTO is about 10 4 around radio frequency at room temperature, which is also thermal stable between 100 and 600 K [1][2][3]. A different effect, the nonlinear electrical behavior of pure and doped CCTO, has also been studied by many researchers [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Grain size effect on the giant dielectric and nonlinear electrical behaviors of Bi1/2Na1/2Cu3Ti4O12 ceramics

et al. 2012

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Single phase Bi 1/2 Na 1/2 Cu 3 Ti 4 O 12 (BNCTO) ceramics with different grain sizes (1.4-4.3 µm) are prepared by a modified Pechini method to investigate their giant dielectric and nonlinear electrical behaviors. The results show that the giant dielectric and nonlinear electrical behaviors are strongly dependent on grain size. With the increment of grain size, the dielectric constant increases monotonically from 14110 (for 1.4 µm sample) to 36183 (for 4.3 µm sample) at 1 kHz, in accompaniment with the breakdown voltage reducing from 112.5 to 43.2 V/mm and the nonlinear coefficient reducing from 4.9 to 3.4. On the basis of the internal barrier layer capacitor (IBLC) model and the IBLC model of Schottky-type potential barrier, an interpretation of the grain size effect on the giant dielectric and nonlinear electrical behaviors is presented.

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Section: Introductionmentioning

confidence: 99%

Grain size effect on the giant dielectric and nonlinear electrical behaviors of Bi1/2Na1/2Cu3Ti4O12 ceramics

et al. 2012

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“…Asimismo, la variación de este coeficiente en los intervalos 1-10 mA/cm 2 y 2-20 mA/cm 2 es pequeña. En resumen, las propiedades no óhmicas del CCTO sinterizado sin el agregado de dopantes, no son suficientemente buenas como para ser usados en dispositivos varistores [25][26][27].…”

Section: Resultados Y Discusiónunclassified

Comportamiento dieléctrico de cerámicos de CaCu3Ti4O12

Ramajo¹,

Reboredo²,

Castro³

2011

Bol. Soc. Esp. Ceram. Vidr.

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En este trabajo se prepararon cerámicos basados en CaCu 3 Ti 4 O 12 (CCTO) por reacción en estado sólido a 900°C y posterior sinterizado a 1100°C. Mediante difracción de rayos X (DRX) se comprobó la presencia de CCTO. A través de espectroscopía Raman se observó la presencia de una fase secundaria rica en CuO. Las mediciones de espectroscopía de impedancia demostraron que este material presenta una constante dieléctrica mayor a 13.000ε 0 en el intervalo comprendido entre 25 y 10 6 Hz. Este valor es atribuido a la presencia de mecanismos de polarización de carga espacial y dipolar. Palabras claves: CaCu 3 Ti 4 O 12, propiedades dieléctricas. Dielectrical behaviour of CaCu 3 Ti 4 O 12 ceramicsIn this work, CaCu 3 Ti 4 O 12 (CCTO) ceramics were prepared by solid state reaction at 900°C for 12 h and sintered at 1100°C during 3 h. The main phase detected through X-ray diffraction (XRD) was CCTO. Also, by means of Raman spectroscopy, it was observed a secondary phase rich in CuO. A dielectric constant higher than 13.000ε 0 was obtained by Impedance spectroscopy measurements in the range between 25 to 10 6 Hz. The value could be explained by the effect of dipolar and space charge polarization processes.Keywords: CaCu 3 Ti 4 O 12, dielectric properties. INTRODUCCIÓNLa reducción de las dimensiones de los componentes electrónicos, tanto pasivos como activos, genera en la industria la necesidad de contar con materiales de elevada constante dieléctrica, principalmente en la fabricación de dispositivos involucrados en sistemas de comunicación wireless, memorias RAM dinámicas y dispositivos de microondas [1][2][3]. En este sentido, la perovskita cúbica distorsionada de fórmula CaCu 3 Ti 4 O 12 (CCTO) [4] presenta, en su forma policristalina, una muy elevada constante dieléctrica (>10.000ε 0 ). Estas propiedades, que se mantienen invariables en un amplio intervalo de temperaturas (100 y 600 K), permiten el uso de estos materiales en dispositivos ferroeléctricos o relaxores.El origen de la elevada constante dieléctrica de los cerámicos de CCTO aun no ha sido bien comprendido y no puede ser atribuida a una transición de fase, como en el caso de los cerámicos basados en titanato de bario. Varios investigadores han propuesto teorías o modelos relacionados la presencia de bordes de grano, de defectos intrínsecos (vacancias de oxígeno) presentes en "twin boundaries" [5] o defectos planares [6][7] dentro del material o de barreras en la interfase existente entre la superficie entre la muestra y el electrodo. Sin embargo, la explicación del fenómeno es aun investigada. Vol 50, 4, 207-212, Julio-Agosto 2011 ISSN 0366-3175. eISSN 2173-0431. doi: 10.3989/cyv.272011 Boletín de la Sociedad Española de Cerámica y VidrioA partir de los resultados de espectroscopia de impedancia, se concluye que uno de los modelos que mejor explica el alto valor de la constante dieléctrica, tanto para muestras cerámicas como películas, es la formación de una estructura de Condensadores de Barreras Internas (IBLC) [8]. En el caso de monocristales la presencia d...

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“…The dielectric constant of CCTO is almost temperature independent, with a temperature range between 100 K and 600 K [2][3][4]. It also has a very small frequency dependence of up to 10 5 Hz [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…It also has a very small frequency dependence of up to 10 5 Hz [5,6]. Such weak temperature and frequency dependencies for CCTO's dielectric constant have attracted much researcher interest because it is an ideal material in a wide range of applications, especially in microelectronics [2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Structural and phase evolution in mechanically alloyed calcium copper titanate dielectrics

Alizadeh

Ardakani

Amini

et al. 2013

Ceramics International

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Nanocrystalline calcium-copper-titanate (CCTO) dielectric powders were prepared by mechanical alloying. Phase transformations and structural evolution of the mechanically activated powders were investigated through the Rietveld refinement of the X-ray diffraction results. The crystallite size, lattice strain, and weight fraction of individual phases were estimated based on crystal structure refinement. Furthermore, the microstructural properties and thermal behavior of the milled powders were investigated by Transmission Electron Microscopy (TEM) and Differential Thermal Analysis (DTA), respectively. It was found that CCTO nanocrystals can be successfully synthesized after the amorphization of the initial crystalline materials. Semi-spherical nano-size particles were developed after sufficient milling time. Formation of an amorphous phase during the milling cycle was confirmed by the presence of the glass transition and crystallization peaks in the thermal analysis profiles.

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Influence of vanadium on electrical and microstructural properties of CaCu3Ti4O12/CaTiO3

Cited by 37 publications

References 33 publications

Grain size effect on the giant dielectric and nonlinear electrical behaviors of Bi1/2Na1/2Cu3Ti4O12 ceramics

Grain size effect on the giant dielectric and nonlinear electrical behaviors of Bi1/2Na1/2Cu3Ti4O12 ceramics

Comportamiento dieléctrico de cerámicos de CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>

Structural and phase evolution in mechanically alloyed calcium copper titanate dielectrics

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