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  • 11
    Electronic Resource
    Electronic Resource
    Phase relations in the system of (Na1/2Bi1/2)TiO3–PbTiO3. II. Dielectric property (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 388-392 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The region of the phase diagram in the system (Na1/2Bi1/2)1−xPbxTiO3 from x=0 to 0.2 was established using dielectric measurements along with the phase diagram established in part I of this work. The diffuse phase transition behavior of solid solutions with low PbTiO3 content was also investigated. When x is lower than xrc (composition at which rhombohedral↔cubic transition exists) the rhombohedral↔tetragonal transition accompanied an anomaly in the ε(T) curve which shows an abrupt jump, followed by diffuse behavior of the ε(T) curve during heating. When xrc〈x〈xMPB (rhombohedral–tetragonal morphotropic phase boundary composition at room temperature) the rhombohedral↔tetragonal transition was a normal ferroelectric-to-ferroelectric transition but the tetragonal↔cubic transition showed diffuse behavior following the abrupt jump in the ε(T) curve. The temperature of the structural change coincided with the abrupt jump in ε(T) curve. Normal ferroelectric phase transition from ferroelectric tetragonal to paraelectric cubic was found when x(approximately-greater-than)xMPB. It was found that the temperature range of the reported antiferroelectric phase would follow that of the diffuse transition range regardless of the crystal symmetry. It can be said that the antiferroelectric phase of (Na1/2Bi1/2)1−xPbxTiO3 is strongly connected with the diffuse transition behavior during ferroelectric phase transition. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360842
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  • 12
    Electronic Resource
    Electronic Resource
    Interface reactions between manganese zinc ferrite single crystals and SiO2-PbO-ZnO ternary systems (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 7045-7052 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Interface reactions between Mn-Zn ferrite single crystals and SiO2-PbO-ZnO ternary systems were investigated using scanning electron microscope, electron probe microanalyzer, and x-ray diffractometer. The addition of ZnO in a SiO2-PbO glass resulted in inhibition of formation of the intermediate phase and suppression of dissolution of the ferrite. The interface morphology became a dendrite structure with increase of ZnO concentration in the glass. Appearance of the anomalous concentration profile of Zn and Mn at the ferrite adjacent to the interface was investigated in terms of the dissolved quantity of Mn and Zn ion. It was found that Zn ion has dissolved from the ferrite into the glass melt during the reaction and Mn ion in the ferrite dissolved into the glass melt more than Zn ion, resulting in changing the undissolved ferrite adjacent to the interface into a Zn-rich Mn-Zn ferrite, Mn0.16Zn0.85Fe2O4, after reaction with 57SiO2-38PbO-5ZnO (in mol %) glass. It was considered that the source of the hump of Zn concentration at the ferrite adjacent to the interface would be the undissolved, remaining Zn ions. A microscopic model was suggested. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360408
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  • 13
    Electronic Resource
    Electronic Resource
    Origin of the increase in resistivity of manganese–zinc ferrite polycrystals with oxygen partial pressure (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 7835-7841 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In our present study, the origin of the increase in resistivity of polycrystalline Mn0.47Zn0.47Fe2.06O4 with increasing oxygen partial pressure was investigated by measuring thermoelectric power and electrical resistivity, and through analysis of grain size. The ferrous ion (Fe2+) concentration of the samples was estimated using the thermoelectric power data and it indicated that the increase of oxygen partial pressure accompanied only a 0.5 wt. % decrease in the concentration of Fe2+. The decrease in Fe2+ concentration failed to explain the order of magnitude increase in resistivity. Preferential oxidation of the grain boundaries did not contribute to the increase in resistivity since all the samples were cooled under the same conditions, i.e., constant oxidation potential. Impedance spectroscopy revealed that the increase in resistivity arose from the increase in resistivity of the grain boundary; this is discussed in terms of the microscopic shape factor, the brick-layer model, and the Maxwell–Wagner model. It is suggested that the increase in resistivity, with increasing oxygen partial pressure, originates from the increase in the microscopic shape factor of the grain boundary. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365393
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  • 14
    Electronic Resource
    Electronic Resource
    Phase relations in the system of (Na1/2Bi1/2)TiO3–PbTiO3. I. Structure (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 383-387 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The region of the (Na1/2Bi1/2)1−xPbxTiO3 phase diagram from 0≤x≤0.2 was established through analysis of structure and thermal anomalies associated with changes in temperature and composition. The rhombohedral-tetragonal morphotropic phase boundary (MPB) was investigated considering the dependence of the rhombohedral lattice distortion of (Na1/2Bi1/2)TiO3 (NBT) on chemical stoichiometry and fabrication processes. It was found that the MPB would lie in the composition range 0.13〈x〈0.15 when the lattice constant and lattice distortion of (Na1/2Bi1/2)TiO3 are 3.886 A(ring) and 89.6°, respectively. The phase transition sequence of (Na1/2Bi1/2)1−xPbxTiO3 was rhombohedral↔tetragonal↔cubic as that of pure NBT when x was less than MPB composition. However, the intermediate tetragonal phase has either low tetragonal distortion for compositions with x〈xrc (composition where rhombohedral↔cubic transition exists) or high tetragonal distortion for compositions with x(approximately-greater-than)xrc. The changes in structure and phase transition behavior of this solid solution system with temperature and composition are discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362702
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  • 15
    Electronic Resource
    Electronic Resource
    Line width of manganese–zinc ferrite polycrystals with oxygen partial pressure : The 7th joint MMM-intermag conference on magnetism and magnetic materials (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 6873-6875 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A systematic variation in line width at X band (9.78 GHz) with oxygen partial pressure was observed in Mn0.47Zn0.47Fe2.06O4 polycrystalline samples. The linewidth of the samples increased from 105 to 188 Oe with decreasing atmospheric parameters from 8.4 to 6.4. It was found that contribution of anisotropy and porosity to the linewidth was small compared to the variation in linewidth with oxygen partial pressure. Estimation of the Fe2+ concentration of samples by measuring their thermoelectric power revealed that an increase in the concentration from 1.88 to 2.44 wt % was accompanied by decreasing oxygen partial pressure. As the resistivity of grain does not vary with oxygen partial pressure, the contribution of eddy current will be the same irrespective of the oxygen partial pressure. Therefore, the systematic increase in linewidth observed in our present study was attributed to the increase in Fe2+ concentration with decreasing oxygen partial pressure. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.367829
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  • 16
    Electronic Resource
    Electronic Resource
    Correlation between strain and dielectric properties in ZrTiO4 thin films (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3043-3045 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-phase paraelectric ZrTiO4 thin films were synthesized at various temperatures using direct-current magnetron reactive sputtering. The dielectric constants (cursive-epsilon) and dielectric losses (tan δ) of as-deposited and annealed films were measured in the 100 kHz range using a Pt upper electrode and a phosphorous-doped Si (100) bottom electrode. Data showed that as the deposition temperature increased, the dielectric losses decreased, while the dielectric constants did not change much. Similar trends for dielectric losses were observed after annealing at 800 °C. These results of dielectric losses correlated well with strains in ZrTiO4 thin films, analyzed from x-ray diffraction peak widths at various scattering angles. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126573
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  • 17
    Electronic Resource
    Electronic Resource
    Phase Evolution and Dielectric Properties of MgTiO3–CaTiO3-Based Ceramic Sintered with Lithium Borosilicate Glass for Application to Low Temperature Co-Fired Ceramics (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Effects on phase evolution caused by the addition of a new sintering agent, lithium borosilicate, Li2O·B2O3·SiO2 (LBS) glass to 0.9MgTiO3–0.1CaTiO3 ceramic and resultant dielectric properties were investigated. The added LBS glass, a liquid phase sintering agent, significantly lowered the densification temperature from 1300° to about 950°C, while yielding decomposition of MgTiO3 into MgTi2O5 and Mg2TiO4. At the same time, the by-products of the decomposition reaction, MgO and TiO2, were dissolved into the glass network. Such phase evolution partly compensated the influence of deleterious glass addition so that the specimen demonstrated fairly good apparent dielectric properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00453.x
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  • 18
    Electronic Resource
    Electronic Resource
    Origin of Microwave Dielectric Loss in ZnNb2O6-TiO2 (2002)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 85 (2002), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: (1−x)ZnNb2O6·xTiO2 ceramics were prepared using both anatase and rutile forms of TiO2. At a composition of x= 0.58, a mixture region of ixiolite (ZnTiNb2O8) and rutile was observed and the temperature coefficient of resonant frequency (τf) was ∼0 ppm/°C. We found that although ɛr and τf were comparable, the quality factor (Q×f, Q≈ 1/ tan δ, f= resonant frequency) of 0.42ZnNb2O6·0.58TiO2 prepared from anatase and rutile was 6000 and 29 000, respectively. The origin of the difference in Q×f of both samples was investigated by measuring electrical conductivity and by analysis of the anatase–rutile phase transition. The anatase-derived sample had higher conductivity, which was related to the reduction of Ti4+. It is suggested that the increase of dielectric loss originates from an increase in Ti3+ and oxygen vacancies due to an anatase–rutile phase transition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2002.tb00240.x
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  • 19
    Electronic Resource
    Electronic Resource
    Effect of Nb2O5/ZnO Addition on Microwave Properties of (Zr0.8Sn0.2)TiO4 Ceramics (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effects of Nb2O5 and ZnO addition on the dielectric properties, especially the quality factor, of (Zr0.8Sn0.2)TiO4 (ZST) ceramics were investigated in terms of the sintered density acquired by the zinc. For ZST ceramics with 2 mol% added ZnO, the relative density of the samples decreased with 〉0.5 mol% addition of Nb2O5. On the other hand, for samples with 6 mol% added ZnO, the relative density remained 〉97%, even when the amount of Nb2O5 was increased to 2.0 mol%. When 〉0.5 mol% Nb2O5 was added, both the quality factor and the dielectric constant exhibited similar trends with sintered density. The ZST ceramics with 6 mol% added ZnO, especially, still manifested a quality factor 〉40 000 and a dielectric constant of 37, even when the amount of Nb2O5 was increased, values that are not explainable by the previously suggested electronic defect model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb01050.x
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  • 20
    Electronic Resource
    Electronic Resource
    Influence of Copper(II) Oxide Additions to Zinc Niobate Microwave Ceramics on Sintering Temperature and Dielectric Properties (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of CuO additions on the firing temperature of ZnNb2O6 ceramics was investigated using dilatometry, transmission electron microscopy, and X-ray diffractometry. A 5 wt% CuO addition to ZnNb2O6 ceramics significantly lowered the firing temperature from 1150° to ∼900°C. The presence of a CuO-rich intergranular phase in the specimen was observed and was evidence of the formation of a liquid phase during sintering. The composition of the liquid phase was (ZnCu2)Nb2O8. In particular, the low-fired ZnNb2O6 ceramics had good microwave dielectric characteristics—Q×f= 59 500, ɛr= 22.1, τf=–66 ppm/oC. These properties were correlated with the formation of a second phase, (ZnCu2)Nb2O8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb00830.x
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