Effects of Co doping on magnetic and electrochemical properties of BiFeO3 nanoparticles

Khajonrit, Jessada; Wongpratat, Unchista; Kidkhunthod, Pinit; Pinitsoontorn, Supree; Maensiri, Santi

doi:10.1016/j.jmmm.2017.10.092

Cited by 89 publications

(24 citation statements)

References 52 publications

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“…Most models that are used to understand the heating process are based on Rosensweig's theory [22] where, as an approximation, the saturation magnetization is considered to be constant with temperature. However, it is well-established that the saturation magnetization of nanoparticles changes significantly with temperature [23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

2017

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Abstract:Understanding saturation magnetization and its behavior with particle size and temperature are essential for medical applications such magnetic hyperthermia. We report the effect of shell thickness and field cooling on the saturation magnetization and its behavior with temperature in Fe 3 O 4 /γ-Fe 2 O 3 core/shell nanoparticles of fixed core diameter (8 nm) and several shell thicknesses. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM)) were used to investigate the phase and the morphology of the samples. Selected area electron diffraction (SAED) confirmed the core/shell structure and phases. Using a SQUID (San Diego, CA, USA), magnetic measurements were conducted in the temperature range of 2 to 300 K both under zero field-cooling (ZFC) and field-cooling (FC) protocols at several field-cooling values. In the ZFC state, considerable enhancement of saturation magnetization was obtained with the increase of shell thickness. After field cooling, we observed a drastic enhancement of the saturation magnetization in one sample up to 120 emu/g (50% larger than the bulk value). In both the FC and ZFC states, considerable deviations from the original Bloch's law were observed. These results are discussed and attributed to the existence of interface spin-glass clusters which are modified by the changes in the shell thickness and the field-cooling.

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Section: Introductionmentioning

confidence: 99%

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

2017

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“…It indicates that during charging of the electrode (i.e., oxidation), the oxidation states of Co 3+ /Co 2+ will shift toward Co 4+ ,and during discharge (i.e., reduction), the oxidation states as Fe 2+ and Co 3+ /Co 2+ will be achieved. [ 48,49 ] The oxidation and reduction peaks in KOH electrolyte can be represented by the following reactions [ 5,50 ]

{Fe}^{2 +} + 2 {OH}^{-} \leftrightarrow Fe {(OH)}_{2}

Fe {(OH)}_{2} + {OH}^{-} \leftrightarrow FeOOH + {normalH}_{2} O + {normale}^{-}

{Co}^{2 +} + 2 {OH}^{-} \leftrightarrow Co {(OH)}_{2}

Co {(OH)}_{2} + 3 {OH}^{-} \leftrightarrow CoOOH + {normalH}_{2} O + {normale}^{-}

CoOOH + {OH}^{-} \leftrightarrow {CoO}_{2} + {normalH}_{2} O + {normale}^{-}

…”

Section: Resultsmentioning

confidence: 99%

Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y₂FeCoO₆

Devi

Kumar

Кумар

2020

Physica Status Solidi (a)

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Citric acid and ethylene glycol assisted hydrothermal synthesis of pure-phase double perovskite oxide Y 2 FeCoO 6 is reported. The Rietveld refinement confirm the orthorhombic phase formation with Pnma space group symmetry and lattice parameters as, a ¼ 5.5039 Å, b ¼ 7.4734 Å, and c ¼ 5.2094 Å. The high-resolution transmission electron micrographs exhibit formation of flakes, composed of agglomerated crystallites, oriented in [121] direction. The oxidation states of Fe as Fe 3þ and Co as Co 2þ /Co 3þ are observed by X-ray photoelectron spectroscopy. The room temperature relative permittivity, 6.8 Â 10 4 , is found to increase to 1.3 Â 10 7 at 473 K and frequency 500 Hz. The specific capacitance of %31.32 F g À1 is obtained at the current density of 1 A g À1. The effective charge storage involve the redox reactions of Fe 2þ /Fe 3þ , Co 2þ /Co 3þ , and Co 3þ /Co 4þ , and excellent capacitance retention of %99% is achieved after 5000 charging/ discharging cycles at current density of 6 A g À1 .

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“…Thus, to obtain nanoparticles of iron oxides with the required characteristics, it is necessary to study the defectiveness and fine details of the local atomic structure of nanoparticles. EXAFS and XANES methods, due to their high sensitivity to the coordination number and changes in the local atomic structure, are important tools for analyzing the phase composition of nanoparticles and the local atomic structure of iron oxide nanoparticles [ 61 ].…”

Section: Spectroscopic Methods For Spion Local Atomic Structure Stmentioning

confidence: 99%

The Local Atomic Structure of Colloidal Superparamagnetic Iron Oxide Nanoparticles for Theranostics in Oncology

2018

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The paper contains an overview of modern spectroscopic methods for studying the local atomic structure of superparamagnetic nanoparticles based on iron oxide (SPIONs), which are an important class of materials promising for theranostics in oncology. Practically important properties of small and ultra small nanoparticles are determined primarily by their shape, size, and features of the local atomic, electronic, and magnetic structures, for the study of which the standard characterization methods developed for macroscopic materials are not optimal. The paper analyzes results of the studies of SPIONs local atomic structure carried out by X-ray absorption spectroscopy at synchrotron radiation sources and Mössbauer spectroscopy during the last decade.

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Effects of Co doping on magnetic and electrochemical properties of BiFeO3 nanoparticles

Cited by 89 publications

References 52 publications

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y₂FeCoO₆

The Local Atomic Structure of Colloidal Superparamagnetic Iron Oxide Nanoparticles for Theranostics in Oncology

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Effects of Co doping on magnetic and electrochemical properties of BiFeO3 nanoparticles

Cited by 89 publications

References 52 publications

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y2FeCoO6

The Local Atomic Structure of Colloidal Superparamagnetic Iron Oxide Nanoparticles for Theranostics in Oncology

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Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y₂FeCoO₆