The influence of Mg doping on the materials properties of Ba1−xSrxTiO3 thin films for tunable device applications

Cole, M. W.; Joshi, P. C.; Ervin, M. H.; Wood, M. C.; Pfeffer, Robert

doi:10.1016/s0040-6090(00)01059-2

Cited by 224 publications

(116 citation statements)

References 18 publications

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“…As shown in Figure 2(c), the spectrum with green color and the one with blue are similar in the contents of elements, just a little variation of strontium and oxygen contents (9.39 at% Sr in the green one, 7.39 at% Sr in the blue one). The atomic ratio of elements in these two spectrums was calculated and was consistent with the desired ratio of Mg doped BST ceramics [2,3,5], which can be assumed as the chemical phase of matrix. However, the spectrum presented as red color showed the apparently high Mg content compared to the matrix (16 at% vs. 1 at%).…”

Section: Resultssupporting

confidence: 60%

“…Barium strontium titanate (BST) materials have shown the great potential for dielectric applications because of their high tenability and low dielectric losses [1]. In the BST system, the additive of MgO or Mg doping in BST ceramics will change the perovskite ABO 3 structure of BST, which leads to the significant suppression of permittivity and losses [2,3]. However, the solubility limit of Mg content in the BST ceramics will affect the microstructure and dielectric properties of BST ceramics [2,4,5].…”

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confidence: 99%

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Microstructure of Ba0.615Sr0.35Mg0.035TiO3 dielectric ceramics via X-ray spectrum analysis

Wen

Xue

et al. 2012

Chin. Sci. Bull.

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The compound Ba 0.615 Sr 0.35 Mg 0.035 TiO 3 was analyzed by the X-ray dispersed spectroscopy analyzer (SEM-EDAX) with the spectrum image method, a powerful tool for chemical phase identification. The method was first time applied on a ceramic material to collect spectrum image and was progressed to identify the Mg-enriched component with fine scale pocket shown in matrix. This result, together with the stoichiometry result obtained from spot mode spectrum analysis, strongly confirmed the microstructure and properties of dielectric materials. Barium strontium titanate (BST) materials have shown the great potential for dielectric applications because of their high tenability and low dielectric losses [1]. In the BST system, the additive of MgO or Mg doping in BST ceramics will change the perovskite ABO 3 structure of BST, which leads to the significant suppression of permittivity and losses [2,3]. However, the solubility limit of Mg content in the BST ceramics will affect the microstructure and dielectric properties of BST ceramics [2,4,5]. Because of the low levels of the additives, it is necessary to directly detect the distribution of complex components in the materials. Energy dispersive X-ray spectrum (EDS) mapping, in which the complete X-ray spectrum is collected at every pixel in the sample, is a new and powerful tool for materials characterization [6][7][8][9]. Spectrum mapping is different from the conventional element mapping (regions of interest mapping, ROI mapping), in which only windows around preselected energy ranges are acquired and only the chosen elements are showed. In the spectrum mapping method, the entire spectrum information is collected at each pixel in spectrum mapping as the beam is rastered across the specimen [7]. This technology allows even unexpected elemental features to be detected after data has been collected. Additionally, the elemental distribution and a corresponding image describing the distribution for each chemical component in the microstructure are offered with this new analysis tool [9]. The new class of energy dispersive X-ray spectrometer, the silicon drift detector (SDD) with less accumulation time and better energy resolution [6,10,11] than the conventional Si-EDS, make it possible to get the compositional nature of the materials with the spectrum imaging analysis.Although some studies on the diffusion of components of alloy [12,13] and the chemical phases segregation near the interface in the metal-ceramic braze [14] by X-ray spectrum analysis, the composition and phase distribution of compound ceramics are not statistically analyzed with this new and efficient spectrum image analysis. In this paper, the microstructure of Ba 0.615 Sr 0.35 Mg 0.035 TiO 3 ceramics is studied with X-ray spectrum mapping techniques, which are used to describe the chemical composition and distribution of the phase in Mg doping BST dielectric ceramics.

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Section: Resultssupporting

confidence: 60%

mentioning

confidence: 99%

Microstructure of Ba0.615Sr0.35Mg0.035TiO3 dielectric ceramics via X-ray spectrum analysis

Wen

Xue

et al. 2012

Chin. Sci. Bull.

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“…9,[87][88][89][90][91][92] The most popular implementation of phase shifters is using the distributed transmission line phase shifter (DTLPS), where the varactors are typically shunt loading the transmission lines periodically. 9,89 By varying the capacitance, the phase velocity and hence the relative phase shift between the input and output can be accomplished. Typical phase shifters require both low insertion loss and high phase shift.…”

Section: Phase Shifters For Electronic Steering Of Antenna Arraysmentioning

confidence: 99%

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

Subramanyam¹,

Cole²,

Sun³

et al. 2013

Journal of Applied Physics

144

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There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated in different multiferroic heterostructures, which show giant voltage control of the ferromagnetic resonance frequency of more than two octaves. This manuscript reviews recent advances in the processing, and application development for the complex oxides and multiferroics, with the focus on voltage tunable RF/microwave components. The over-arching goal of this review is to provide a synopsis of the current state-of the-art of complex oxide and multiferroic thin film materials and devices, identify technical issues and technical challenges that need to be overcome for successful insertion of the technology for both military and commercial applications, and provide mitigation strategies to address these technical challenges. V C 2013 AIP Publishing LLC.

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“…[3][4][5] The restrain to practical tunable device applications of ferroelectric materials is their dielectric loss tangent. 6 In particular, Fe 2+ , Mn 2+ , Mn 3+ , and Sc 3+ , which can occupy the B sites of the ABO 3 perovskite structure, have been known to lower dielectric loss.…”

mentioning

confidence: 99%

“…6 In particular, Fe 2+ , Mn 2+ , Mn 3+ , and Sc 3+ , which can occupy the B sites of the ABO 3 perovskite structure, have been known to lower dielectric loss. 5,[7][8][9] On the other hand, it was found that introducing of low dielectric loss layers into the interface of BST and electrodes could obtain tunable thin films with low loss tangent. 10 However, permittivity of such BST films decreased as the dielectric loss induced, so did the tunability.…”

mentioning

confidence: 99%

Dielectric properties of Ba0.6Sr0.4TiO3 thin films using Pb0.3Sr0.7TiO3 buffer layers

Wang

Hao

et al. 2007

Applied Physics Letters

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TiO 3 ͑PST͒ at each side of the interface contact with electrodes ͑PST/BST/PST͒ were deposited on Pt/ Ti/ SiO 2 / Si substrates. The dielectric properties of the films were measured using planar Pt/ PST/ BST/ PST/ Pt/ Ti/ SiO 2 / Si capacitor structures. The existence of a PST layer between the BST and Pt electrode can improve the dielectric properties of the BST film. The loss tangent of the multilayered films annealed at 750°C was found to be 0.016 at 1 MHz and room temperature. The films showed a ϳ31.7% tunability of the permittivity at an applied bias field of 0.85 MV/ cm. This suggests that such films have potential applications for integrated device applications.

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The influence of Mg doping on the materials properties of Ba1−xSrxTiO3 thin films for tunable device applications

Cited by 224 publications

References 18 publications

Microstructure of Ba0.615Sr0.35Mg0.035TiO3 dielectric ceramics via X-ray spectrum analysis

Microstructure of Ba0.615Sr0.35Mg0.035TiO3 dielectric ceramics via X-ray spectrum analysis

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

Dielectric properties of Ba0.6Sr0.4TiO3 thin films using Pb0.3Sr0.7TiO3 buffer layers

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