Low-temperature synthesis of single-phase Co7Sb2O12

Brito, Maria S.L; Escote, M. T.; Santos, Carlos Oliveira Paiva; Lisboa‐Filho, Paulo Noronha; Leite, E. R.; Oliveira, José de; Gama, L.; Longo, Elson

doi:10.1016/j.matchemphys.2004.08.008

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…As already pointed out, the n 1 band is assigned to SbO 6 vibration. The small variation observed in its position is due to the interaction among the octahedra, which are condensed in spinels [19]. Moreover, since the four infrared active modes belong to the same T 1u representation, the vibrations could interact [20].…”

Section: Resultsmentioning

confidence: 94%

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Color and structural analysis of CoxZn7−xSb2O12 pigments

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Paskocimas

et al. 2006

Materials Research Bulletin

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The polymeric precursor method was successfully used to synthesize Co x Zn 7Àx Sb 2 O 12 (x = 0-7) powders. Pigments were evaluated using colorimetry, X-ray diffraction, UV-vis and infrared spectroscopy. The optical band gap values vary with the Co 2+ substitution. These results suggest that the concomitant presence of Co and Zn in the spinel lattice leads to the rupture of the Végard law, as well as other properties of the studied system, such as unit cell volume. The Co-richer samples display a higher absorbance than the Co-lean samples. The high absorption of the Co 7 Sb 2 O 12 sample at most of the visible region makes this compound a candidate for a black pigment. It was shown that color depends on the site where the chromophore ion is located, in agreement with the ligand field theory. #

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Section: Resultsmentioning

confidence: 94%

“…According to Brito et al [19], the band n 1 could be attributed to vibrations of the ions of higher valence Sb 5+ in the octahedral sites. The n 2 band may be due to cobalt vibrations in the octahedral sites or, perhaps, to a mixed vibration of the cobalt ions in tetrahedral and octahedral sites.…”

Section: Resultsmentioning

confidence: 97%

Color and structural analysis of CoxZn7−xSb2O12 pigments

Gouveia

Soledade

Paskocimas

et al. 2006

Materials Research Bulletin

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“…For example, these materials have been used as diluted magnetic semiconductors (DMS), − catalysts, , thermistors, and pigments, among others. , Spinel compounds with pentavalent (Zn 7 Sb 2 O 12 ) and divalent (Co 7 Sb 2 O 12 ) cations have shown high potential as ceramic varistors . In particular, the binary spinel Co 7 Sb 2 O 12 has attracted interest, since the ion distribution of Co 2+ in the tetrahedral and octahedral sites into the spinel structure can be affected by the high valence of the Sb 5+ ion and high sintering temperatures. , Physical properties of spinel oxides depend on the cation distribution through the tetrahedral and octahedral sites in the structure, as Co 2+ ions occupy both sites but have a preference for octahedral sites and Sb 5+ is restricted to octahedral sites; when Li is added to Co 7 Sb 2 O 12 , a new solid solution is obtained and the cation distribution changes, consequently modifying the physical properties. Accordingly, it was recently shown that Li 3 x Co 7–4 x Sb 2+ x O 12 solid solutions exhibit nonohmic properties with a high electric field threshold like those common ceramic varistors as of ZnO and SnO 2 .…”

Section: Introductionmentioning

confidence: 99%

Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions

et al. 2023

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In this work, the thermal properties of ternary Li3x Co7–4x Sb2+x O12 solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li+ and Sb5+, accompanied by the reduction of Co2+, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.

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“…The cation distribution was (Li 0.47 Fe 0.53 ) A (Li 0.53 Fe 0.47 Ti) B O 4 , implying that both A- and B-sublattices (subscripts in the formula) are magnetically diluted. It is noteworthy that as a consequence of substitutions by diamagnetic titanium atoms from the parent phase Li 0.5 Fe 2.5 O 4 , a competition between the exchange interactions ( J AB , J AA , and J BB ) appears, giving rise to a large number of disordered states such as a localized canted state (LCS), Yafet-Kittel (YK) state, semi-spin-glass (SSG) state, spin-glass (SG) state, cluster spin-glass state (CSG), and so forth. According to these possibilities, there are a good number of papers devoted to the interpretation of the magnetic behavior in this system. ,,,− …”

Section: Introductionmentioning

confidence: 99%

Magnetic Behavior of the LiFeTiO₄ Spinel

et al. 2005

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The LiFeTiO4 spinel obtained by the “liquid mix” technique has been studied by neutron powder diffraction, ac and dc magnetic susceptibility, and magnetization measurements. The cationic distribution in the tetrahedral (A) and octahedral (B) sites was determined to be (Li0.47Fe0.53)A(Li0.53Fe0.47Ti)BO4. The dc magnetic susceptibility measurements show two maxima at 29 and 282 K (at H = 1000 Oe) and a Curie−Weiss behavior is not observed in the temperature range 282−800 K. Neutron diffraction patterns shows that the B-site magnetic moments at 2 K temperature are lower than those expected for a collinear arrangement of spins. Careful analyses of the low-temperature neutron diffraction patterns of this material suggest a localized canting of spins (LCS) type of magnetic ordering where a long-range order (LRO) of longitudinal component of moments coexists along with a totally disordered transverse component of moments. The conclusion is also supported by the features seen in complementary magnetic measurements.

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Low-temperature synthesis of single-phase Co7Sb2O12

Cited by 8 publications

References 18 publications

Color and structural analysis of CoxZn7−xSb2O12 pigments

Color and structural analysis of CoxZn7−xSb2O12 pigments

Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions

Magnetic Behavior of the LiFeTiO₄ Spinel

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Low-temperature synthesis of single-phase Co7Sb2O12

Cited by 8 publications

References 18 publications

Color and structural analysis of CoxZn7−xSb2O12 pigments

Color and structural analysis of CoxZn7−xSb2O12 pigments

Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions

Magnetic Behavior of the LiFeTiO4 Spinel

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Magnetic Behavior of the LiFeTiO₄ Spinel