Crystal structure and related properties of copper-doped barium titanate ceramics

Langhammer, H. T.; Müller, Thomas; Böttcher, R.; Abicht, Hans‐Peter

doi:10.1016/s1293-2558(03)00087-6

Cited by 70 publications

(52 citation statements)

References 21 publications

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“…If direct paths were formed, it would be expected that short circuits would develop between top and bottom electrodes. Copper oxide would be expected to act as a 2 + B site dopant and function as an acceptor ion in the BaTiO 3 host lattice [20,21]. Such acceptor doping would be expected to harden the electromechanical response by lowering the permittivity and increasing the coercive field -neither consequence is apparent [22].…”

Section: Resultsmentioning

confidence: 99%

Copper Compatible Barium Titanate Thin Films for Embedded Passives

et al. 2005

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Barium titanate thin films have been prepared by chemical solution deposition on 18 µm thick, industry standard copper foils in the absence of chemical barrier layers. The final embodiment exhibits randomly oriented BaTiO 3 grains with diameters between 0.1 and 0.3 µm, and an equiaxed morphology. The average film thickness is 0.6 µm and the microstructure is free from secondary or interfacial phases. The BaTiO 3 films are sintered in a high temperature reductive atmosphere such that copper oxidation is avoided. Subsequent lower-temperature, higher oxygen pressure anneals are used to minimize oxygen point defects. Permittivities of 2500 are observed at zero bias and room temperature, with permittivities greater than 3000 at the coercive field. Loss tangents under 1.5% are demonstrated at high fields. The BaTiO 3 phase exhibits pronounced ferroelectric switching and coercive field values near 10 kV/cm. Temperature dependent measurements indicate a ferroelectric transition near 100 • C with very diffuse character. Combining the approaches of the multilayer capacitor industry with traditional solution processed thin films has allowed pure barium titanate to be integrated with copper. The high sintering temperature-as compared to typical film processing-provides for large grained films and properties consistent with well-prepared ceramics. Integrating BaTiO 3 films on copper foil represents an important step towards high capacitance density embedded passive components and elimination of economic constraints imparted by traditional noble metallization.

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Section: Resultsmentioning

confidence: 99%

Copper Compatible Barium Titanate Thin Films for Embedded Passives

et al. 2005

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“…EPR was also employed in copper-doped electro-optic [68], in which the observed EPR spectra were simulated by a superposition of axial and isotropic Cu 2+ spectra of unknown origin. In Cu 2+ :BaTiO 3 ceramics, also two superposed copper centers were observed [69]. Depending on doping level and sintering temperature, the EPR data exhibited two different Cu Ti spectra with g > g ⊥ > g e each, attributed to tetragonally distorted CuO 6 octahedra in tetragonal and rhombohedral crystal surroundings, respectively.…”

Section: Cu 2+ Centermentioning

confidence: 95%

Defect structure of oxide ferroelectrics—valence state, site of incorporation, mechanisms of charge compensation and internal bias fields

2007

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The defect structure of aliovalent transitionmetal and rare-earth functional centers in ferroelectric perovskite oxides is characterized by means of multifrequency electron paramagnetic resonance spectroscopy, assisted by density-functional theory calculations. The review is mainly focused on lead zirconate titanate (Pb[Zr x Ti 1−x ]O 3 , PZT) compounds. However, where available also results on ferroelectric 'lead-free' compounds are discussed. The results include the formation of charged (Fe Zr,Ti − V •• O ) • defect dipoles, causing internal bias fields, multivalence manganese centers, acceptor-type copper functional centers creating isolated oxygen vacancies that promote ionic conductivity, as well as Gd • Pb donor-type centers. Moreover, the impact of the defect structure on macroscopic material properties is discussed.

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“…BaTiO 3 (BT) is a common lead-free ferroelectric material and has a sharp peak of permittivity at a Curie temperature (T c ¼ 400 K). [1][2][3][4][5] BT based solid solution has been widely studied for many applications, e.g. multilayer ceramic capacitors, to enhance permittivity and/or to broaden the peak temperature.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Property of Polycrystalline ZrO2 Substituted BaTi2O5 Prepared by Arc-Melting

Yue

Goto

2008

Mater. Trans.

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ZrO 2 substituted polycrystalline BaTi 2 O 5 , Ba(Ti 1Ày Zr y ) 2 O 5 , (BT 2 Z), was prepared by arc-melting and the dielectric property was investigated by AC impedance spectroscopy. The length of a-axis increased from 1.6895 to 1.6952 nm and that of c-axis increased from 0.9411 to 0.9436 nm with increasing y up to 0.06. The b-axis was almost independent of ZrO 2 content. The solubility limit of ZrO 2 (y) in BT 2 Z can be 0.06. BT 2 Z had a strong b-axis orientation at y < 0:06. The permittivity of BT 2 Z at y ¼ 0:005 showed the highest peak of 3050 at 725 K and the peak temperature decreased from 750 to 465 K with increasing y from 0 to 0.064. A relaxor-like frequency dependence of permittivity was observed at y > 0:06.

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Crystal structure and related properties of copper-doped barium titanate ceramics

Cited by 70 publications

References 21 publications

Copper Compatible Barium Titanate Thin Films for Embedded Passives

Copper Compatible Barium Titanate Thin Films for Embedded Passives

Defect structure of oxide ferroelectrics—valence state, site of incorporation, mechanisms of charge compensation and internal bias fields

Dielectric Property of Polycrystalline ZrO<SUB>2</SUB> Substituted BaTi<SUB>2</SUB>O<SUB>5</SUB> Prepared by Arc-Melting

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