Oxygen stoichiometry effects in spinel‐type NiMn2O4−δ samples

Lisboa‐Filho, Paulo Noronha; Bahout, Mona; Barahona, P.; Moure, C.; Peña, O.

doi:10.1016/j.jpcs.2005.03.001

Cited by 57 publications

(35 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Redox titration techniques were used to determine manganese valence fluctuations, and by charge-equilibrium arguments the oxygen content of the samples can be estimated. The average obtained result indicated that the oxygen stoichiometry for the sample as it was prepared was 3-δ=2.90 (±0.05) [15]. X-ray diffraction analyses associated with Rietveld refinement confirm that the synthesized erbium manganese oxide sample (ErMnO 3 ) is single phase with hexagonal symmetry and a P6 3 cm space group.…”

Section: Resultsmentioning

confidence: 88%

See 1 more Smart Citation

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

et al. 2011

View full text Add to dashboard Cite

Manganese-based oxides present a very complex magnetic phase diagram, and many of their basic physical properties and magnetic interaction need more exploration. At the crystallographic level, the magnetic properties of rare-earth oxide manganites are strongly affected by changes in the rare-earth ion present in the structure, the nature of the transition metals, and the possibility of electronic valence fluctuations. This work studied the synthesis procedure and structural and magnetic characterization of high-quality polycrystalline samples of the ErMn 1-x Co x O 3-δ family. Crystallographic analyses show a decrease in lattice parameters as cobalt substitution increases, accompanied by a reduction in the interatomic distances and a small increase in MT-O-MT angles (MT= cobalt and manganese) considering the c-axis. Magnetic measurements indicated a phase separation picture, and show the coexistence of different magnetic interactions with the samples considering the Mn/Co ratio. In addition, the spin-inversion mechanism is interpreted as having a crucial role in the family's magnetic response.

show abstract

Section: Resultsmentioning

confidence: 88%

“…These dissolved salts were mixed with citric acid solution at a metal/chelating agent proportion of 1:3. After 1 h at 60°C, the solution was polymerized by adding ethylene glycol at a citric acid/ethylene glycol mass ratio of 60:40 [15]. The chelation and polymerization reactions are outlined in Fig.…”

Section: Methodsmentioning

confidence: 99%

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

et al. 2011

View full text Add to dashboard Cite

show abstract

“…At the same time, for spinels of other compositions, in particular NiMn 2 O 4±δ [21] and Cd [22,23], oxygen stoichiometry was found to exert a certain effect on magnetic characteristics. In the former compound oxygen stoichiometry greatly influences the magnetic interactions between the ferromagnetic and antiferromagnetic sublattices due to the presence of manganese in three possible valence states.…”

Section: Participation Of Octahedral Comentioning

confidence: 92%

Magnetic properties of Zn_0.7Co_2.3O₄₊δ spinel prepared by thermal decomposition of binary oxalates in air

Базуев

Гырдасова

2008

Physica Status Solidi (b)

View full text Add to dashboard Cite

Magnetization and ac susceptibility of two Zn0.7Co2.3O4+δ spinel specimens obtained by decomposition of the binary oxalate Znx Co1–x C2O4·2H2O in air were measured in the temperature range 2–300 K. It is shown that the complex oxide Zn0.7Co2.3O4+δ formed right after the decomposition of the oxalate (at 220 °C) contains about 0.002 mass% metal cobalt, which is responsible for the dependence of the magnetic susceptibility χ on magnetic field at 300 K. Below 100 K, the χ = f (T) dependence of this specimen is characterized by divergence between curves measured under ZFC and FC conditions and a magnetic hysteresis loop at 2 K. The specimen synthesized at 700 °C does not contain a ferromagnetic component and is paramagnetic in the temperature interval 2–300 K. The observed differences in magnetic properties are explained by a higher degree of oxidation of cobalt and the nanodimensional state of the compound formed at a lower temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

“…19 In summary, previous work on bulk NMO magnetism demonstrates that any investigation of anomalous magnetic properties in NMO must include studies of the cation inversion and valences.…”

Section: +mentioning

confidence: 95%

“…Previous work on the magnetism of NMO demonstrates that the bulk magnetism can be profoundly altered by changing the distribution and oxidation state of the Ni and Mn cations, while still maintaining a T C of 110 K. 4,[14][15][16][17]19 In general, studies have found that bulk NMO contains Ni 2+ , Mn 2+ , Mn 3+ and Mn 4+ cations, and cation inversion parameters (ν) ranging from 0.74 < ν < 0.95. 4,15,16 For reference, cation inversion is defined along a continuum between…”

Section: -11mentioning

confidence: 99%

Modified magnetic ground state inNiMn2O4thin films

et al. 2010

View full text Add to dashboard Cite

We demonstrate the stabilization of a magnetic ground state in epitaxial NiMn2O4 (NMO) thin films not observed in their bulk counterpart. Bulk NMO exhibits a magnetic transition from a paramagnetic phase to a collinear ferrimagnetic moment configuration below 110 K and to a canted moment configuration below 70 K. By contrast, as-grown NMO films exhibit a single magnetic transition at 60 K and annealed films exhibit the magnetic behavior found in bulk. Cation inversion and epitaxial strain are ruled out as possible causes for the new magnetic ground state in the asgrown films. However a decrease in the octahedral Mn 4+ :Mn 3+ concentration is observed and likely disrupts the double exchange that produces the magnetic state at intermediate temperatures. Xray magnetic circular dichroism and bulk magnetometry indicate a canted ferrimagnetic state in all samples at low T. Together these results suggest that the collinear ferrimagnetic state observed in bulk NMO at intermediate temperatures is suppressed in the as grown NMO thin films due to a decrease in octahedral Mn 4+ , while the canted moment ferrimagnetic ordering is preserved below 60 K.

show abstract

Oxygen stoichiometry effects in spinel‐type NiMn2O4−δ samples

Cited by 57 publications

References 22 publications

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

Magnetic properties of Zn_0.7Co_2.3O₄₊δ spinel prepared by thermal decomposition of binary oxalates in air

Modified magnetic ground state inNiMn2O4thin films

Contact Info

Product

Resources

About

Oxygen stoichiometry effects in spinel‐type NiMn2O4−δ samples

Cited by 57 publications

References 22 publications

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-δ samples

Magnetic properties of Zn0.7Co2.3O4+δ spinel prepared by thermal decomposition of binary oxalates in air

Modified magnetic ground state inNiMn2O4thin films

Contact Info

Product

Resources

About

Magnetic properties of Zn_0.7Co_2.3O₄₊δ spinel prepared by thermal decomposition of binary oxalates in air