Magnetic Dielectric Oxides: Subsolidus Phase Relations in the BaO:Fe2O3:TiO2System

Vanderah, Terrell A.; Loezos, J. M.; Roth, Robert

doi:10.1006/jssc.1996.0006

Cited by 65 publications

(66 citation statements)

References 9 publications

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“…Rectangular grains in Fig.4 decomposition to form both end members in the system at 1150C. 10,11) In this study, the Ba 2 Fe 6 O 11 ss phase could be detected in the composite samples fabricated by sintering at 1250C.…”

Section: Phase and Microstructure Changes With Fe Contentmentioning

confidence: 51%

Permittivity Change of NiZn Ferrite–BaTiO₃Composites with Fe Content

Abe

Kitahara

Higuchi

et al. 2009

Jpn. J. Appl. Phys.

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Ceramic composites were fabricated from powder mixtures of BaTiO 3 and Ni 0.3 Zn 0.7 Fe x O 4± with different Fe contents of x = 1.8, 1.9, 2.0, 2.1, and 2.2 to examine the effect of the Fe content on the dielectric permittivity (r) of the composite samples. The r values of the composites were greatly affected by the Fe content such that a small r value of the Fe1.8 composite sample steeply increased with an increasing Fe content by about three orders of magnitude for the Fe2.1 and Fe2.2 samples. The strong Fe content dependence could be correlated with the incorporation of the Ti 4+ ions into the octahedral sublattices in the ferrite structure. The Ti-substitution would preferentially contribute to charge compensation for the Fe-poor ferrites, whereas it should result in the creation of the Fe 2+ ions on the octahedral sublattices of the Fe-rich ferrite phases.Therefore, the presence of the Fe 2+ ions synergetically created by the Ti-substitution and Fe-rich composition would be responsible for the considerably increasing r values for the Fe2.1 and Fe2.2 composite samples.

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Section: Phase and Microstructure Changes With Fe Contentmentioning

confidence: 51%

Permittivity Change of NiZn Ferrite–BaTiO₃Composites with Fe Content

Abe

Kitahara

Higuchi

et al. 2009

Jpn. J. Appl. Phys.

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“…Ba 2 Ti 9 O 19 and BaTi 4 O 9 ), and strongly magnetic compounds such as barium hexaferrite (BaFe 12 O 19 ). The phase diagram study confirmed the formation of a number of ternary phases with new structural types, including the title compound, denoted previously as phase ''G'' [3] with a stoichiometry close to ''Ba 14 Fe 2 Ti 35 O 87 '' (ϭ 0.28:0.02:0.70 BaO:Fe 2 O 3 :TiO 2 ), as estimated by the disappearing phase method. The present report describes the crystal structure and more precise stoichiometry of this compound, as determined by single-crystal and X-ray powder diffraction methods, and characterization of its dielectric and magnetic properties.…”

Section: Introductionmentioning

confidence: 62%

“…( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) investigated [3] to elucidate compounds forming between the high-dielectric-constant polytitanates (e.g. Ba 2 Ti 9 O 19 and BaTi 4 O 9 ), and strongly magnetic compounds such as barium hexaferrite (BaFe 12 O 19 ).…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Properties of Ba₁₁FeTi₂₇O_66.5

Vanderah

Siegrist²,

Roth

et al. 2004

Eur J Inorg Chem

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The crystal structure of Ba 11 FeTi 27 O 66.5 was determined using single-crystal and powder X-ray diffraction methods. This phase crystallizes in the monoclinic space group C2/m (No. 12) (a = 23.324(1) Å , b = 11.388(1) Å , c = 9.8499(3) Å , β = 90.104(3)°; Z = 2; ρ calcd. = 4.98 g/cm 3 ), and exhibits a 10-layer structure built from close-packed [O,(Ba,O) , with some preferential ordering suggested by analysis of bond valence sums. The structure features vertex-, edge-, and face-sharing of the [Ti(Fe)O 6 ] octahedra. Indexed X-ray powder diffraction data for a polycrystalline specimen are given. Ba 11 FeTi 27 O 66.5 and the 8-layer phase Ba 4 Fe 2 Ti 10 O 27 are built from the same types of polyhedral layers, some of which feature vacant sites between two Ba ions, which substitute for three oxygens in a row. The single-crystal results suggest that the basic structural formula of the phase is A 11 B 28 O 66+x , with the value of x (and hence the Fe/Ti ratio) determined by partial occupancy of one of these vacant sites. Variation of this occupancy factor with synthesis temperature may account for apparent slight differences in the stoichiometry of this phase in polycrystalline and single-crystal form. However, solid solution forma-

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“…2. The XRD patterns of FeTiO3 oxidized at different temperatures for 4 h show that the FeTiO3 samples are slowly oxidized for temperature range of 600-1000 °C and completely oxidized above 1000 °C for 4 h. This is why the pure hexagonal phase is formed for only 0.06 Fedoped BaTiO3 reported by Vanderah et al [10] by using multiple one week heatings at 1250-1270 °C as the temperature and the time of this study are higher than 1100 °C/4 h. While Khirade et al [11] found that the tetragonal phase is stable for (x = 0.0 to 0.3) and the mixed phase of the tetragonal and hexagonal structure is stable in the sample with higher Fe concentration (x = 0.4 and 0.5) as the temperature used is 900°C…”

Section: Resultsmentioning

confidence: 93%