Synthesis, magnetic properties and Mössbauer spectroscopy for the pyrochlore family Bi2BB′O7 with B=Cr and Fe and B′=Nb, Ta and Sb

Blanco, Marìa Cecilia; Franco, D. G.; Jalit, Yamile; Miner, Elisa Victoria Pannunzio; Berndt, Graciele; Paesano, Andrea; Nieva, G.; Carbonio, R. E.

doi:10.1016/j.physb.2011.12.029

Cited by 17 publications

(4 citation statements)

References 14 publications

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“…Using a single doublet component to fit the spectrum did not accurately reproduce the profile, while using two quadrupolar components allows the line shape to be satisfactorily modeled. The same situation has been reported previously for other Fe containing pyrochlores, such as (Bi 1.8 Fe 0.2 )(FeSb)O 7 and Bi 2 BB′O 7 (where B = Cr or Fe, and B′ = Nb, Ta, and Sb) . These studies concluded that the two observed components were due to small amounts of iron that were located on the A site with the majority on the B site of the structure; however, in the current study the two component fit to the Mössbauer data could equally be due to the presence of chemical disorder in the crystal structure.…”

Section: Resultssupporting

confidence: 90%

Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

et al. 2014

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The hydrothermal syntheses, structures, and magnetism of two new pyrochlore oxides of compositions (Na0.60Bi1.40)(Fe1.06Mn0.17Bi0.77)O6.87 and (K0.24Bi1.51)(Fe1.07Mn0.15Bi0.78)O6.86 are described. With preparation at 200 °C for 6 h in solutions of sodium or potassium hydroxide, the alkali metals introduced from these mineralizers are essential to the synthesis of the phases. The average long-range order of the pyrochlore structure, with space group Fd3̅m, was investigated and refined against X-ray and neutron diffraction data, and it was shown that disorder is present in both the metal and coordinating oxygen positions, along with metal-mixing across both the A and B sites of the structure. XANES analysis confirms the presence of Mn(4+), mixed valence Bi(3+) and Bi(5+), and Fe(3+), the last also verified by (57)Fe Mössbauer spectroscopy. Magnetic measurements show a lack of long-range magnetic ordering that is typical of geometrically frustrated pyrochlores. The observed glasslike interactions occur at low temperatures, with the onset temperature depending upon the magnitude of the applied external field. Variable temperature X-ray diffraction shows that these pyrochlores are metastable and collapse on heating at ca. 395 °C, which suggests that their formation by conventional solid-state synthesis would be impossible.

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Section: Resultssupporting

confidence: 90%

Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

et al. 2014

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“…5) can be related to the iron in paramagnetic and paraelectric regular phase that was observed on the XRD pattern. The second much smaller one could be ascribed to iron in pyrochlore impurity phase that is also evidenced at the XRD pattern, and the obtained IS value is in the range 0.40-0.49 mm/s, which was previously reported for pyrochlores of similar composition [23].…”

Section: Mössbauer Spectroscopysupporting

confidence: 81%

Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO₃-0.5Pb(Fe_0.5Ta_0.5)O₃ solid solution

et al. 2017

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IntroductionMaterials that exhibit ferromagnetic and ferroelectric ordering in the same phase are named magnetoelectrics, which are part of a larger group of multiferroics. Multiferroics possess at least two ferroic orderings at the same time. Magnetoelectric materials are characterized by a strong coupling between the magnetic and electric subsystems, which means that the magnetic fi eld is able to induce electric polarization and vice versa.The fi rst single-phase multiferroic perovskite oxides (ABO 3 ) were discovered in early 1960s. However, very limited progress has been made during the past several decades [1][2][3][4][5][6]. The signifi cant development of multiferroic materials started with the successful synthesis of multiferroic thin fi lms [7].Magnetoelectrics are widely used as transducers, actuators, detectors, and other sensors that are characterized by high dielectric permittivity and magnetic permeability [1][2][3][4][5][6][7] Abstract. Multiferroic 0.5BiFeO 3 -0.5Pb(Fe 0.5 Ta 0.5 )O 3 solid solution is a material that exhibits ferroelectric and antiferromagnetic orderings in ambient temperature. The solid solution was obtained as a result of a conventional reaction in a solid state. The obtained material is a dense, fi ne-grained sinter whose surface was observed by scanning electron microscopy (SEM) and stoichiometry was confi rmed by energy dispersive X-ray spectroscopic (EDS) analysis. According to the X-ray powder diffraction (XRD) measurements, the main phase is R3c space group with admixture of Pm-3m regular phase. Small contribution of pyrochlore-like phase was also observed. Mössbauer spectroscopy suggested random distribution of Fe 3+ /Ta 5+ cations in the B sites of ABO 3 compound. Reduction of the magnetic hyperfi ne fi eld with an increase in the substitution of Ta 5+ in Fe 3+ neighbourhood was also observed.

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“…Reflecting this trend, we could not prepare the Pr 2 SbFeO 7 and Nd 2 SbFeO 7 pyrochlores without a second doublet (i.e., the largest one) in their Mössbauer spectra, even after many synthesis tries, at different heat treatment temperatures. We attribute this second subspectrum to iron cations occupying the RE site (16c), in the same way it was observed for Bi 2 FeMO 7 (M = Ta and Sb) pyrochlores [18]. Throughout some unknown mechanism, larger ionic radii (i.e., 0.99 Å, 0.983 Å and 1.03 Å, for Pr 3+ , Nd 3+ and Bi 3+ , respectively) favor the occupancy of site 16c by Fe 3+ cations.…”

Section: Mössbauer Spectroscopysupporting

confidence: 72%

“…Such Bi-deficient pyrochlores were, eventually, found in poly-phase systems [15][16][17]. Another interesting feature associated with the site disorder is the displacive disorder, frequently observed through the (4 4 2) reflection in the PXRD patterns [18,15]. However, this did not appear in any of the materials studied here.…”

Section: Powder X-ray Diffractionmentioning

confidence: 66%

Structural, hyperfine and Raman properties of RE2FeSbO7 compounds

Berndt

Silva

Ivashita

et al. 2015

Journal of Alloys and Compounds

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Synthesis, magnetic properties and Mössbauer spectroscopy for the pyrochlore family Bi2BB′O7 with B=Cr and Fe and B′=Nb, Ta and Sb

Cited by 17 publications

References 14 publications

Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO₃-0.5Pb(Fe_0.5Ta_0.5)O₃ solid solution

Structural, hyperfine and Raman properties of RE2FeSbO7 compounds

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Synthesis, magnetic properties and Mössbauer spectroscopy for the pyrochlore family Bi2BB′O7 with B=Cr and Fe and B′=Nb, Ta and Sb

Cited by 17 publications

References 14 publications

Metastable (Bi, M)2(Fe, Mn, Bi)2O6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Metastable (Bi, M)2(Fe, Mn, Bi)2O6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5)O3 solid solution

Structural, hyperfine and Raman properties of RE2FeSbO7 compounds

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Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Metastable (Bi, M)₂(Fe, Mn, Bi)₂O_6+x (M = Na or K) Pyrochlores from Hydrothermal Synthesis

Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO₃-0.5Pb(Fe_0.5Ta_0.5)O₃ solid solution