Nadejda Horchidan | Universitatea Alexandru Ioan Cuza Iasi, Romania (original) (raw)

Papers by Nadejda Horchidan

Journal of the American Ceramic Society, Dec 12, 2023

Surfaces and interfaces, Aug 1, 2024

Ceramics International, May 1, 2016

The objective of present study is an investigation of the role of mixing level (from macro-to mic... more The objective of present study is an investigation of the role of mixing level (from macro-to microscale) on the dielectric and ferroelectric properties of doped lead zirconium titanate (PZT) composites with soft/hard counterparts. The composites were prepared by two types of doped PZT (soft and hard), which were mixed on a macroscopic (chessboard) and a microscopic level and densified using a classical sintering procedure. A combined scanning electron microscopy, and atomic force microscopy were performed to obtain new insights about microstructure modifications of the investigated ceramic composites. The dielectric properties and high field and ferroelectric properties demonstrated that the soft behavior is prevailing when using macro-scale mixing, while the micro-scale mixing favors the hard behavior. Therefore, the dominant (soft or hard) behavior can be modified by using different scale mixing methods, providing a possible method of controlling the functional characteristics of PZT-based composites.

Social Science Research Network, 2023

Journal of the European Ceramic Society

Materials

Lead-free piezoelectric ceramics with nominal composition at morphotropic phase boundary Ba0.85Ca... more Lead-free piezoelectric ceramics with nominal composition at morphotropic phase boundary Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) prepared by different processing routes and sintered either by conventional solid-state reaction or by spark plasma sintering (SPS) techniques were comparatively investigated to observe the role of structural modifications and of microstructures on the dielectric, ferroelectric, piezoelectric and electrocaloric responses. The ceramics presented relative densities from 75% to 97% and showed variations in their phase composition as a result of variable mixing and different synthesis and sintering parameters providing local compositional heterogeneity. As result, all of the ceramics showed diffuse phase transition and ferroelectric switching responses, with parameters affected mostly by density (Pr between 3.6 to 10.1 μC/cm2). High values for the electrocaloric response in the Curie range were found for the ceramics with predominantly orthorhombic character. Field-in...

ACS Applied Materials & Interfaces

Materials

BaTiO3 (BTO) nanoparticles produced by wet chemistry methods were embedded in several types of fl... more BaTiO3 (BTO) nanoparticles produced by wet chemistry methods were embedded in several types of flexible materials in order to fabricate flexible electronic devices. Starting from the produced nanoparticle dielectric properties, flexible material dielectric properties were tested for high electromagnetic frequencies (30 GHz–2 THz) using time domain spectroscopy. Dielectric performances of the different materials obtained with variable nanoparticle concentrations up to 40 wt.%, embedded in, gelatin, epoxy, and styrene-butadiene were compared at several working temperatures between 0 °C and 120 °C. Beside the general trend of ε′ decrease with temperature and loses increase with the operating frequency, we were able to identify few matrix dependent optimal nanoparticle concentrations. The best composite performances were achieved by the BTO-SBS matrix, with filler concentration of 2 wt.%, where the losses have been of 1.5%, followed by BTO-gelatin matrix, with filler concentration of 40...

Nanomaterials, 2022

The role of Ag addition on the structural, dielectric, and mechanical harvesting response of 20%(... more The role of Ag addition on the structural, dielectric, and mechanical harvesting response of 20%(xAg − (1 − x)BaTiO3) − 80%PVDF (x = 0, 2, 5, 7 and 27 vol.%) flexible composites is investigated. The inorganic fillers were realized by precipitating fine (~3 nm) silver nanoparticles onto BaTiO3 nanoparticles (~60 nm average size). The hybrid admixtures with a total filling factor of 20 vol.% were embedded into the PVDF matrix. The presence of filler enhances the amount of β-PVDF polar phase and the BaTiO3 filler induces an increase of the permittivity from 11 to 18 (1 kHz) in the flexible composites. The addition of increasing amounts of Ag is further beneficial for permittivity increase; with the maximum amount (x = 27 vol.%), permittivity is three times larger than in pure PVDF (εr ~ 33 at 1 kHz) with a similar level of tangent losses. This result is due to the local field enhancement in the regions close to the filler-PVDF interfaces which are additionally intensified by the presen...

Journal of Alloys and Compounds, 2022

Abstract The modifications of structural and functional properties induced by the gradual increas... more Abstract The modifications of structural and functional properties induced by the gradual increase of porosity from 4 vol% to 26 vol% produced by addition of polymeric sacrificial templates in BaTiO3 ceramics were investigated in detail. With respect to other previous studies concerning porous ceramics, the present ones show a phase superposition around room temperature, whose relative amount impact on their functional properties. Low/high porosity favours the orthorhombic/tetragonal symmetry, respectively. Permittivity and polarisation (both irreversible and reversible ones) regularly decrease when reducing ceramic density, while dc tunability and P(E) loops of denser ceramics have shown peculiar features at intermediate fields, i.e. modifications of hysteretic-nonhysteretic character of e ( E ) dependences at about± (8–10) kV/cm and wasp-waisted P(E) loops. To explain such effects, a simplified Landau-based approached considering variable shear stress contributions (higher in dense ceramics, lower in porous ones) was developed to examine the stability of orthorhombic/tetragonal states as a function of stress and applied field levels. The simulations indicated for dense ceramics the possibility of a field-induced structural transformation at intermediate field range overlapped on the general trend of stress-induced increasing of orthorhombic amount. The porosity-induced modification of properties in BaTiO3 ceramics is related to the value of porosity itself which reduces the amount of ferroelectric active phase, to possible modifications of pore connectivity at various porosity levels, but also by modifications of internal stress level induced by porosity, which impact on the polymorph phase composition.

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2020

The phase formation and functional properties (dielectric, ferroelectric switching, and tunabilit... more The phase formation and functional properties (dielectric, ferroelectric switching, and tunability) in <inline-formula> <tex-math notation="LaTeX">${x}$ </tex-math></inline-formula>BaGeO₃–(<inline-formula> <tex-math notation="LaTeX">$1- {x}$ </tex-math></inline-formula>)BaTiO₃ ceramics with compositions <inline-formula> <tex-math notation="LaTeX">${x} =0$ </tex-math></inline-formula>, 0.01, 0.018, 0.1, 0.68, and 1, produced by solid-state reaction, are presented. For small Ge additions <inline-formula> <tex-math notation="LaTeX">${x} \le {0.10}$ </tex-math></inline-formula> for which the perovskite tetragonal phase is predominant, the low-field dielectric properties are quite similar to ones of BaTiO₃ ceramics, with all the structural phase transitions in the same temperature range and a small shift of the Curie temperature to higher values when increasing Ge addition. The eutectic composition <inline-formula> <tex-math notation="LaTeX">${x} = {0.68}$ </tex-math></inline-formula> is a composite containing mostly nominal amounts of hexagonal <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>-BaGeO₃ phase and tetragonal BaTiO₃, and shows permittivity below 100 and a lossy linear dielectric character, with zero tunability and lack of switching, similar as the BaGeO₃ composition (<inline-formula> <tex-math notation="LaTeX">${x} = {1}$ </tex-math></inline-formula>). The role of Ge in increasing the density by liquid-phase sintering is beneficial for improving the electrical properties. In this sense, the composition <inline-formula> <tex-math notation="LaTeX">${x} = {0.10}$ </tex-math></inline-formula> is optimum in the present ceramic series: it shows the highest relative density of 99% and large grains (tens of micrometers), excellent switching properties with the highest polarization and a rectangular switching loop, the highest permittivity above room temperature and a good <inline-formula> <tex-math notation="LaTeX">$\varepsilon ({E})$ </tex-math></inline-formula> tunability of 60%–70%, comparable with the best values reported in other BaTiO₃ solid solutions.

Journal of the European Ceramic Society, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Ceramics International, 2019

The present paper reports the dependence of structural and functional properties on the porosity ... more The present paper reports the dependence of structural and functional properties on the porosity level with values down to 50% in BaTiO 3 ceramics. Micro-porosity (pore size below 15 μm) with (0-3) connectivity has been produced by using dried pollen particles as sacrificial template. The properties of such porous ceramics are mostly affected by porosity, but also by possible small doping with foreign ions resulted from the template and by small variations of Ba/Ti stoichiometry at the ceramic-pore interfaces, as observed by a shift of the Curie temperature towards lower values when porosity level increases. The dielectric relaxation evidenced a few processes characterised by different activation energies which seem to be not affected by porosity, i.e. they might be assigned to the ceramic part and not to the ceramic-pore interfaces. When increasing porosity, a regular tilting of P(E) loops and increasing of coercivity and reducing polarization were observed, as result of reduction of active ferroelectric component and to the field inhomogeneity in such ceramics.

Processing and Application of Ceramics, 2017

3D Finite Element Method simulations were employed in order to describe tunability properties in ... more 3D Finite Element Method simulations were employed in order to describe tunability properties in anisotropic porous paraelectric structures. The simulations predicted that properties of a ceramic can be tailored by using various levels of porosity. Porous Ba0.6Sr0.4TiO3 (BST) ceramics have been studied in order to investigate the influence of porosity on their functional properties. The BST ceramics with various porosity levels have been obtained by solid-state reaction. Lamellar graphite in different concentration of 10, 20 and 35 vol.%was added as sacrificial pore forming agent. The structural, microstructural, dielectric and tunability properties were investigated. By comparison with dense BST ceramic, porous samples present a fracture mode transformation from intragranular to an intergranular fracture and a decrease of grain size. Lower dielectric constants, low dielectric losses, but higher values of tunability than in the dense material were obtained in the porous BST structur...

Acta Materialia, 2018

Abstract Macroscopic properties measurements, such as dielectric permittivity and ferroelectric h... more Abstract Macroscopic properties measurements, such as dielectric permittivity and ferroelectric hysteresis, differential scanning calorimetry, and average structure information are combined with complementary techniques sensitive to the local structure, i.e. Pair Distribution Function (PDF) and Raman spectroscopy, to gain comprehensive insight into the structure-property relationships and origin of relaxor behaviour in BaCexTi1-xO3 ceramics over a broad composition (x = 0.02–0.30) and temperature (100–450 K) range. The resulting phase diagram displays sequential phase transitions with a tricritical point (TCP) at x = 0.09 and a ferroelectric to relaxor crossover (FRC) at x ≈ 0.20. In contrast, the local structure is rhombohedral irrespective of x and the PDF reveals the existence of a high level of disorder and significant local strains determined by the ionic size mismatch (Ce4+: 0.87 A, Ti4+: 0.605 A). The diffuse character of the phase transitions observed when x ≥ 0.05 is most likely originated by these deformations. Parallel of BaMxTi1-xO3 phase diagrams (M = Sn, Hf, Zr, Ce) shows that the compositions corresponding to TCP and FRC are nearly independent of M. This suggests that, irrespective of the ionic radius of M4+, in homovalent-substituted BaTiO3 a critical number of Ti-O-Ti bonds has to be broken before a new “state” is established, whereas local electric and strain fields seem to have a marginal effect.

International Journal of Applied Ceramic Technology, 2017

In the present article, we propose a ferroelectric-based frequency mixer capable of reconfigurabl... more In the present article, we propose a ferroelectric-based frequency mixer capable of reconfigurable functioning, a key trait in multi frequency band coverage, based on the nonlinear dielectric properties of BaSn x Ti 1Àx O 3 ceramics. According to the properties of BaSn x Ti 1Àx O 3 solid solutions, an optimum composition was selected to demonstrate the applicability as a discrete passive mixer with a simple coplanar geometry. A prototype device, with four coplanar capacitors, connected in a circular electric circuit was built on the surface of the selected ceramic. In this configuration, mixing products of the pumping and working signals were obtained and characterized.

Materials Chemistry and Physics, 2016

Please cite this article in press as: M. Airimioaei, et al., Effect of particle size and volume f... more Please cite this article in press as: M. Airimioaei, et al., Effect of particle size and volume fraction of BaTiO 3 powders on the functional properties of BaTiO 3 /poly(ε-caprolactone) composites, Materials Chemistry and Physics (2016), http://dx.doi.org/10.1016/j.matchemphys.2016.07.029 composites with coarser BT particles. The composition x ¼ 0.05 with coarse particles can be considered as an optimum among these series for the stored energy density.

Ceramics International, 2016

Ceramics International, 2016

The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous... more The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba 0.70 Sr 0.30 TiO 3 ceramics, Ceramics International,

Journal of the American Ceramic Society, Dec 12, 2023

Surfaces and interfaces, Aug 1, 2024

Ceramics International, May 1, 2016

The objective of present study is an investigation of the role of mixing level (from macro-to mic... more The objective of present study is an investigation of the role of mixing level (from macro-to microscale) on the dielectric and ferroelectric properties of doped lead zirconium titanate (PZT) composites with soft/hard counterparts. The composites were prepared by two types of doped PZT (soft and hard), which were mixed on a macroscopic (chessboard) and a microscopic level and densified using a classical sintering procedure. A combined scanning electron microscopy, and atomic force microscopy were performed to obtain new insights about microstructure modifications of the investigated ceramic composites. The dielectric properties and high field and ferroelectric properties demonstrated that the soft behavior is prevailing when using macro-scale mixing, while the micro-scale mixing favors the hard behavior. Therefore, the dominant (soft or hard) behavior can be modified by using different scale mixing methods, providing a possible method of controlling the functional characteristics of PZT-based composites.

Social Science Research Network, 2023

Journal of the European Ceramic Society

Materials

Lead-free piezoelectric ceramics with nominal composition at morphotropic phase boundary Ba0.85Ca... more Lead-free piezoelectric ceramics with nominal composition at morphotropic phase boundary Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) prepared by different processing routes and sintered either by conventional solid-state reaction or by spark plasma sintering (SPS) techniques were comparatively investigated to observe the role of structural modifications and of microstructures on the dielectric, ferroelectric, piezoelectric and electrocaloric responses. The ceramics presented relative densities from 75% to 97% and showed variations in their phase composition as a result of variable mixing and different synthesis and sintering parameters providing local compositional heterogeneity. As result, all of the ceramics showed diffuse phase transition and ferroelectric switching responses, with parameters affected mostly by density (Pr between 3.6 to 10.1 μC/cm2). High values for the electrocaloric response in the Curie range were found for the ceramics with predominantly orthorhombic character. Field-in...

ACS Applied Materials & Interfaces

Materials

BaTiO3 (BTO) nanoparticles produced by wet chemistry methods were embedded in several types of fl... more BaTiO3 (BTO) nanoparticles produced by wet chemistry methods were embedded in several types of flexible materials in order to fabricate flexible electronic devices. Starting from the produced nanoparticle dielectric properties, flexible material dielectric properties were tested for high electromagnetic frequencies (30 GHz–2 THz) using time domain spectroscopy. Dielectric performances of the different materials obtained with variable nanoparticle concentrations up to 40 wt.%, embedded in, gelatin, epoxy, and styrene-butadiene were compared at several working temperatures between 0 °C and 120 °C. Beside the general trend of ε′ decrease with temperature and loses increase with the operating frequency, we were able to identify few matrix dependent optimal nanoparticle concentrations. The best composite performances were achieved by the BTO-SBS matrix, with filler concentration of 2 wt.%, where the losses have been of 1.5%, followed by BTO-gelatin matrix, with filler concentration of 40...

Nanomaterials, 2022

The role of Ag addition on the structural, dielectric, and mechanical harvesting response of 20%(... more The role of Ag addition on the structural, dielectric, and mechanical harvesting response of 20%(xAg − (1 − x)BaTiO3) − 80%PVDF (x = 0, 2, 5, 7 and 27 vol.%) flexible composites is investigated. The inorganic fillers were realized by precipitating fine (~3 nm) silver nanoparticles onto BaTiO3 nanoparticles (~60 nm average size). The hybrid admixtures with a total filling factor of 20 vol.% were embedded into the PVDF matrix. The presence of filler enhances the amount of β-PVDF polar phase and the BaTiO3 filler induces an increase of the permittivity from 11 to 18 (1 kHz) in the flexible composites. The addition of increasing amounts of Ag is further beneficial for permittivity increase; with the maximum amount (x = 27 vol.%), permittivity is three times larger than in pure PVDF (εr ~ 33 at 1 kHz) with a similar level of tangent losses. This result is due to the local field enhancement in the regions close to the filler-PVDF interfaces which are additionally intensified by the presen...

Journal of Alloys and Compounds, 2022

Abstract The modifications of structural and functional properties induced by the gradual increas... more Abstract The modifications of structural and functional properties induced by the gradual increase of porosity from 4 vol% to 26 vol% produced by addition of polymeric sacrificial templates in BaTiO3 ceramics were investigated in detail. With respect to other previous studies concerning porous ceramics, the present ones show a phase superposition around room temperature, whose relative amount impact on their functional properties. Low/high porosity favours the orthorhombic/tetragonal symmetry, respectively. Permittivity and polarisation (both irreversible and reversible ones) regularly decrease when reducing ceramic density, while dc tunability and P(E) loops of denser ceramics have shown peculiar features at intermediate fields, i.e. modifications of hysteretic-nonhysteretic character of e ( E ) dependences at about± (8–10) kV/cm and wasp-waisted P(E) loops. To explain such effects, a simplified Landau-based approached considering variable shear stress contributions (higher in dense ceramics, lower in porous ones) was developed to examine the stability of orthorhombic/tetragonal states as a function of stress and applied field levels. The simulations indicated for dense ceramics the possibility of a field-induced structural transformation at intermediate field range overlapped on the general trend of stress-induced increasing of orthorhombic amount. The porosity-induced modification of properties in BaTiO3 ceramics is related to the value of porosity itself which reduces the amount of ferroelectric active phase, to possible modifications of pore connectivity at various porosity levels, but also by modifications of internal stress level induced by porosity, which impact on the polymorph phase composition.

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2020

The phase formation and functional properties (dielectric, ferroelectric switching, and tunabilit... more The phase formation and functional properties (dielectric, ferroelectric switching, and tunability) in <inline-formula> <tex-math notation="LaTeX">${x}$ </tex-math></inline-formula>BaGeO₃–(<inline-formula> <tex-math notation="LaTeX">$1- {x}$ </tex-math></inline-formula>)BaTiO₃ ceramics with compositions <inline-formula> <tex-math notation="LaTeX">${x} =0$ </tex-math></inline-formula>, 0.01, 0.018, 0.1, 0.68, and 1, produced by solid-state reaction, are presented. For small Ge additions <inline-formula> <tex-math notation="LaTeX">${x} \le {0.10}$ </tex-math></inline-formula> for which the perovskite tetragonal phase is predominant, the low-field dielectric properties are quite similar to ones of BaTiO₃ ceramics, with all the structural phase transitions in the same temperature range and a small shift of the Curie temperature to higher values when increasing Ge addition. The eutectic composition <inline-formula> <tex-math notation="LaTeX">${x} = {0.68}$ </tex-math></inline-formula> is a composite containing mostly nominal amounts of hexagonal <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>-BaGeO₃ phase and tetragonal BaTiO₃, and shows permittivity below 100 and a lossy linear dielectric character, with zero tunability and lack of switching, similar as the BaGeO₃ composition (<inline-formula> <tex-math notation="LaTeX">${x} = {1}$ </tex-math></inline-formula>). The role of Ge in increasing the density by liquid-phase sintering is beneficial for improving the electrical properties. In this sense, the composition <inline-formula> <tex-math notation="LaTeX">${x} = {0.10}$ </tex-math></inline-formula> is optimum in the present ceramic series: it shows the highest relative density of 99% and large grains (tens of micrometers), excellent switching properties with the highest polarization and a rectangular switching loop, the highest permittivity above room temperature and a good <inline-formula> <tex-math notation="LaTeX">$\varepsilon ({E})$ </tex-math></inline-formula> tunability of 60%–70%, comparable with the best values reported in other BaTiO₃ solid solutions.

Journal of the European Ceramic Society, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Ceramics International, 2019

The present paper reports the dependence of structural and functional properties on the porosity ... more The present paper reports the dependence of structural and functional properties on the porosity level with values down to 50% in BaTiO 3 ceramics. Micro-porosity (pore size below 15 μm) with (0-3) connectivity has been produced by using dried pollen particles as sacrificial template. The properties of such porous ceramics are mostly affected by porosity, but also by possible small doping with foreign ions resulted from the template and by small variations of Ba/Ti stoichiometry at the ceramic-pore interfaces, as observed by a shift of the Curie temperature towards lower values when porosity level increases. The dielectric relaxation evidenced a few processes characterised by different activation energies which seem to be not affected by porosity, i.e. they might be assigned to the ceramic part and not to the ceramic-pore interfaces. When increasing porosity, a regular tilting of P(E) loops and increasing of coercivity and reducing polarization were observed, as result of reduction of active ferroelectric component and to the field inhomogeneity in such ceramics.

Processing and Application of Ceramics, 2017

3D Finite Element Method simulations were employed in order to describe tunability properties in ... more 3D Finite Element Method simulations were employed in order to describe tunability properties in anisotropic porous paraelectric structures. The simulations predicted that properties of a ceramic can be tailored by using various levels of porosity. Porous Ba0.6Sr0.4TiO3 (BST) ceramics have been studied in order to investigate the influence of porosity on their functional properties. The BST ceramics with various porosity levels have been obtained by solid-state reaction. Lamellar graphite in different concentration of 10, 20 and 35 vol.%was added as sacrificial pore forming agent. The structural, microstructural, dielectric and tunability properties were investigated. By comparison with dense BST ceramic, porous samples present a fracture mode transformation from intragranular to an intergranular fracture and a decrease of grain size. Lower dielectric constants, low dielectric losses, but higher values of tunability than in the dense material were obtained in the porous BST structur...

Acta Materialia, 2018

Abstract Macroscopic properties measurements, such as dielectric permittivity and ferroelectric h... more Abstract Macroscopic properties measurements, such as dielectric permittivity and ferroelectric hysteresis, differential scanning calorimetry, and average structure information are combined with complementary techniques sensitive to the local structure, i.e. Pair Distribution Function (PDF) and Raman spectroscopy, to gain comprehensive insight into the structure-property relationships and origin of relaxor behaviour in BaCexTi1-xO3 ceramics over a broad composition (x = 0.02–0.30) and temperature (100–450 K) range. The resulting phase diagram displays sequential phase transitions with a tricritical point (TCP) at x = 0.09 and a ferroelectric to relaxor crossover (FRC) at x ≈ 0.20. In contrast, the local structure is rhombohedral irrespective of x and the PDF reveals the existence of a high level of disorder and significant local strains determined by the ionic size mismatch (Ce4+: 0.87 A, Ti4+: 0.605 A). The diffuse character of the phase transitions observed when x ≥ 0.05 is most likely originated by these deformations. Parallel of BaMxTi1-xO3 phase diagrams (M = Sn, Hf, Zr, Ce) shows that the compositions corresponding to TCP and FRC are nearly independent of M. This suggests that, irrespective of the ionic radius of M4+, in homovalent-substituted BaTiO3 a critical number of Ti-O-Ti bonds has to be broken before a new “state” is established, whereas local electric and strain fields seem to have a marginal effect.

International Journal of Applied Ceramic Technology, 2017

In the present article, we propose a ferroelectric-based frequency mixer capable of reconfigurabl... more In the present article, we propose a ferroelectric-based frequency mixer capable of reconfigurable functioning, a key trait in multi frequency band coverage, based on the nonlinear dielectric properties of BaSn x Ti 1Àx O 3 ceramics. According to the properties of BaSn x Ti 1Àx O 3 solid solutions, an optimum composition was selected to demonstrate the applicability as a discrete passive mixer with a simple coplanar geometry. A prototype device, with four coplanar capacitors, connected in a circular electric circuit was built on the surface of the selected ceramic. In this configuration, mixing products of the pumping and working signals were obtained and characterized.

Materials Chemistry and Physics, 2016

Please cite this article in press as: M. Airimioaei, et al., Effect of particle size and volume f... more Please cite this article in press as: M. Airimioaei, et al., Effect of particle size and volume fraction of BaTiO 3 powders on the functional properties of BaTiO 3 /poly(ε-caprolactone) composites, Materials Chemistry and Physics (2016), http://dx.doi.org/10.1016/j.matchemphys.2016.07.029 composites with coarser BT particles. The composition x ¼ 0.05 with coarse particles can be considered as an optimum among these series for the stored energy density.

Ceramics International, 2016

Ceramics International, 2016

The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous... more The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba 0.70 Sr 0.30 TiO 3 ceramics, Ceramics International,