Inducing Ferrimagnetism in Insulating Hollandite Ba1.2Mn8O16

Larson, Amber M.; Moetakef, Pouya; Gaskell, Karen J.; Brown, Craig M.; King, Graham; Rodriguez, Efrain E.

doi:10.1021/cm503801j

Cited by 21 publications

(37 citation statements)

References 87 publications

(125 reference statements)

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“…The initial slow decrease in the dielectric constant has been consistent with the Koops model [46]. Moreover, the polycrystalline samples have high grain boundary density and so the nature of the grains and grain boundaries affects the electrical properties [47]. The inhomogeneity occurred because of grains and grain boundaries that lead to high dielectric value.…”

Section: Resultssupporting

confidence: 72%

Magnetic and Dielectric Properties of La and Ni Co-substituted BiFeO3 Nanoceramics

et al. 2020

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The increasing plead for the realization of ultra-fast, miniaturized, compact, and ultra-low power consumption in electronic as well as spintronic devices has propelled the quest for novel multiferroic materials that efficiently enable voltage control of magnetism. The present work reports the phase stability, magnetic and dielectric responses of polycrystalline Bi 1−x La x Fe 1−y Ni y O 3 (0 ≤ x ≥ 0.2 and 0 ≤ y ≥ 0.2) multiferroic ceramics synthesized through a simplistic sol-gel approach. The maneuver substitutions of La at A − site of BiFeO 3 multiferroic eliminate the secondary phases formed owing to impurities. Rietveld refined XRD analysis reveals the structural transformation of the orthorhombic (Pbnm) phase as La substitution increases. However, an additional lattice distortion is induced as a result of the substitutions of Ni atoms at B − site. A substantial enhancement in magnetic and dielectric responses has been found in the co-doped (Ni and La) sample at both A and B − sites as a result of the size confinement of nano-crystallites, the exchange interaction between Fe 3+ and Ni 2+ ions, and corresponding variation in Fe-O-Fe bond angles. The dielectric constant has increased substantially in the low-frequency region with simultaneous substitutions of La and Ni at the sites of Bi and Fe, respectively. A careful observation of temperature-dependent magnetization curves (FC and ZFC) indicates a spin glass response with entangled ferromagnetic components. The experimental findings infer that the co-substitutions of La and Ni at their respective sites in Bi 1−x La x Fe 1−y Ni y O 3 (0 ≤ x ≥ 0.2 and 0 ≤ y ≥ 0.2) may significantly improve the ferromagnetic and dielectric responses of the studied nanoceramics.

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Section: Resultssupporting

confidence: 72%

Magnetic and Dielectric Properties of La and Ni Co-substituted BiFeO3 Nanoceramics

et al. 2020

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“…The 1-D channels in PbIr 4 Se 8 appear distorted in comparison to Hollandite, with Se-Se anion-anion bonding and a Se-Se bond distance of 2.50(2) Å in the smaller 1-D channels. This sort of anion-anion bonding is well known to occur in Ir chalcogenides [23,[34][35][36][37] and leads to a formal electron count of Pb 2+ (Ir 3+ ) 4 (Se 2 ) 2-(Se 2-) 6 , which is in good agreement with bond valence sums for an average Pb position (1.94 (2)), and the material exhibiting diamagnetic behavior (i.e. Ir is low-spin d 6 ).…”

Section: Resultssupporting

confidence: 65%

“…In the case of sulfides, selenides, and tellurides, it appears that it is universally more favorable for Ir to be Ir 3+ with anion-anion bonding. The low-spin 5d 6 compounds.…”

Section: Structural Similarities To Other Hollanditesmentioning

confidence: 99%

Structure, properties, and disorder in the new distorted-Hollandite PbIr4Se8

Trump

McQueen

2016

Journal of Solid State Chemistry

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The synthesis and physical properties of the new distorted-Hollandite PbIr 4 Se 8 are reported. Powder X-ray diffraction and transmission electron microscopy show that the structure consists of edge-and corner-sharing IrSe 6 octahedra, with one-dimensional channels occupied by Pb. The structure contains Se-Se anion-anion bonding, leading to an electron count of Pb 2+ (Ir 3+ ) 4 (Se 2 ) 2-(Se 2-) 6 , confirmed by bond-valence sums and diamagnetic behavior.Structural and heat capacity measurements demonstrate disorder on the Pb site, due to the combination of lonepair effects and the large size of the one-dimensional channels. Comparisons are made to known Hollandite and pseudo-Hollandite structures, which demonstrates that the anion-anion bonding in PbIr 4 Se 8 distorts its structure, to accommodate the Ir 3+ state. An electronic structure calculation indicates semiconductor character with a band gap of 0.76(11) eV.

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“…The general chemical formula of these hollandite‐type materials can be written as A +/2+ x B 2+/3+/4+ 8 O 16 (0 < x < 2), where A‐sites are usually occupied by alkali and or alkaline‐earth elements (eg, Na, K, Rb, Cs, Sr, and Ba) and B‐sites are often occupied by a variety of cations (eg, Mg, Co, Ni, Zn, Al, Ga, Cr, Fe, Ti, and Mn) . Hollandites have been studied for a variety of applications, such oxygen evolution reaction catalysts (K x ≈2 Ir 8 O 16 ), ferromagnetic materials (Ba 1.2 Mn 8 O 16 ), and battery electrode systems with M x Mn 8 O 16 (M = Ag or K) demonstrated as cathodes, and K 2 (M 2 Sn 6 )O 16 (M = Co, In) used as anode materials . In SYNROC‐based materials for nuclear waste immobilization, the multiphase system is based on thermodynamically compatible titanate phases.…”

Section: Introductionmentioning

confidence: 99%

Compositional control of radionuclide retention in hollandite‐based ceramic waste forms for Cs‐immobilization

Zhao

Shuller-Nickles

et al. 2018

J Am Ceram Soc

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Hollandite materials, as a class of crystalline nuclear waste forms, are promising candidates for the immobilization of radioactive elements, such as Cs, Ba, as well as a variety of lanthanide and transition-metal fission products. In this study, three Ga-doped titanate hollandite-type phases, Ba 1.33 Ga 2.67 Ti 5.33 O 16 , Ba 0.667 Cs 0.667 Ga 2 Ti 6 O 16 , and Cs 1.33 Ga 1.33 Ti 6.67 O 16 , were synthesized using a solid-state reaction route. All synthesized phases adopted a single phase tetragonal structure, as determined by powder X-ray diffraction (XRD), and elemental analysis confirmed the measured stoichiometries were close to targeted compositions. Extended X-ray absorption fine structure spectroscopy (EXAFS) was used to determine the local structural features for the framework of octahedrally coordinated cations. EXAFS data indicated that Cs 1.33 Ga 1.33 Ti 6.67 O 16 possessed the most disordered local structure centered around the Ga dopant. The enthalpies of formation of all three hollandite phases measured using high-temperature oxide melt solution calorimetry were found to be negative, indicating enthalpies of formation of these hollandites from oxides are thermodynamically stable with respect to their constituent oxides. Furthermore, the formation enthalpies were more negative and hence more favorable with increased Cs content. Finally, aqueous leaching tests revealed that high Cs content hollandite phases exhibited greater Cs retention as compared to low Cs content hollandite. While preliminary in nature, this work draws attention to the links between the capacity for radionuclide retention, atomistic level structural features and bulk thermodynamic properties of materials.

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Inducing Ferrimagnetism in Insulating Hollandite Ba_1.2Mn₈O₁₆

Cited by 21 publications

References 87 publications

Magnetic and Dielectric Properties of La and Ni Co-substituted BiFeO3 Nanoceramics

Magnetic and Dielectric Properties of La and Ni Co-substituted BiFeO3 Nanoceramics

Structure, properties, and disorder in the new distorted-Hollandite PbIr4Se8

Compositional control of radionuclide retention in hollandite‐based ceramic waste forms for Cs‐immobilization

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