Cation Migration-Induced Crystal Phase Transformation in Copper Ferrite Nanoparticles and Their Magnetic Property

Yadav, Raghvendra Singh; Havlica, Jaromír; Másilko, Jiří; Kalina, Lukáš; Wasserbauer, Jaromír; Hajdúchová, Miroslava; Enev, Vojtěch; Kuřitka, Ivo; Kožáková, Zuzana

doi:10.1007/s10948-015-3339-4

Cited by 62 publications

(43 citation statements)

References 47 publications

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“…43 In the case of RE element (Er, Nd) doped CFO, Hc increased sharply at the low doping and stayed constant at further higher doping level (0-4%), and argued to be due to strong spin-orbit coupling of rare-earth elements. 8,[44][45][46] Similar to the present work, the Zn doped CFO shows decrease in coercivity (525-165 Oe) as a function of doping (0-10%). 47 While we do not have a definite experimental evidence to show whether Mo enters into tetrahedral or octahedral site in CFO lattice, this issue is still under discussion in the literature 32,48 .…”

Section: The Observed Hc In Our Sample Is Consistent With Previous Obsupporting

confidence: 85%

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

et al. 2017

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Melendez, A.; Manadhar, S.; Singamaneni, S. R.; Reddy, Kongara M.; Gandha, Kinjal H.; Niebedim, I. C.; and Ramana, C. V., "Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite" (2017). Ames Laboratory Accepted Manuscripts. 61. AbstractWe report on the effect of molybdenum (Mo) incorporation on the crystal structure, surface morphology, Mo chemical valence state, and magnetic properties of cobalt ferrite (CoFe2O4, referred to CFO). Molybdenum incorporated cobalt ferrite (CoFe2-xMoxO4, referred to CFMO) ceramics were prepared by the conventional solid-state reaction method by varying the Mo concentration in the range of x = 0.0-0.3. X-ray diffraction studies indicate that the CFMO materials crystallize in inverse spinel cubic phase. Molybdenum incorporation induced lattice parameter increase from 8.322 to 8.343 Å coupled with a significant increase in density from 5.4 to 5.7 g/cm3 was evident in structural analyses. Scanning electron microscopy imaging analyses indicate that the Mo incorporation induces agglomeration of particles leading to larger particle size with increasing x(Mo) values. Detailed X-ray photoelectron spectroscopic (XPS) analyses indicate the increasing Mo content with increasing x from 0.0 to 0.3. XPS confirms that the chemistry of Mo is complex in these CFMO compounds; Mo ions exist in the lower oxidation state (Mo4+) for higher x while in a mixed chemical valence state (Mo4+, Mo5+, Mo6+) for lower x values. From the temperature-dependent magnetization, the samples show ferrimagnetic behavior including the pristine CFO. From the isothermal magnetization measurements, we find almost 2-fold decrease in coercive field (Hc) from 2143 to 1145 Oe with the increase in Mo doping up to 30%. This doping-dependent Hc is consistently observed at all the temperatures measured (4, 100, 200, and 300 K). Furthermore, the saturation magnetization estimated at 4 K and at 1.5 T (from M-H loops) goes through a peak at 92 emu/g (at 15% Mo doping) from 81 emu/g (pristine CFO), and starts decreasing to 79 emu/g (at 30% Mo doping). The results demonstrate that the crystal structure, microstructure, and magnetic properties can be tuned by controlling the Mo-content in the CFMO materials. ABSTRACTWe report on the effect of molybdenum (Mo) incorporation on the crystal structure, surface morphology, Mo chemical valence state and magnetic properties of cobalt ferrite (CoFe2O4, referred to CFO). Molybdenum incorporated cobalt ferrite (CoFe2-xMoxO4, referred to CFMO) ceramics were prepared by the conventional solid-state reaction method by varying the Mo concentration in the range of x=0.0-0.3. X-ray diffraction studies indicate that the CFMO materials crystallize in inverse spinel cubic phase. Molybdenum incorporation induced lattice parameter increase from 8.322 to 8.343 Å coupled with a significant increase in density from 5.4 to 5.7 g/cm 3 was evident in structural analyses. Scanning electron microscopy imaging analysis indicate that the Mo incorporation induces agglomeration of pa...

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Section: The Observed Hc In Our Sample Is Consistent With Previous Obsupporting

confidence: 85%

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

et al. 2017

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“…The Fe 2p 3/2 peak can further be fitted into two peaks at ~712.6 and ~710.4 eV which corresponds to the presence of Fe 3+ ions in both octahedral and tetrahedral sites of NiFe 2 O 4 respectively. 44 These observations further indicate that NiFe 2 O 4 has a partial inverse spinel structure. Figure 5c shows the high-resolution XPS spectrum of core level Ni 2p where two peaks were observed at 873.…”

Section: X-ray Photoelectron Spectroscopy Studymentioning

confidence: 74%

“…These peaks correspond to the presence of Fe in the Fe(III) state in the product. 44 The presence of a satellite peak further supporting the absence of the Fe 3 O 4 phase in the composite. The Fe 2p 3/2 peak can further be fitted into two peaks at ~712.6 and ~710.4 eV which corresponds to the presence of Fe 3+ ions in both octahedral and tetrahedral sites of NiFe 2 O 4 respectively.…”

Section: X-ray Photoelectron Spectroscopy Studymentioning

confidence: 87%

NiFe₂O₄nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions

2020

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“…47 The other precursors, starch and gelatin, have been more studied in the sol-gel method synthesis in the last years. [48][49][50] In addition to these procedures the synthesis without any gelling precursor, the blank test, was also performed.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Freitas

Siqueira

Costa

et al. 2017

J. Braz. Chem. Soc.

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Lithium cobalt oxide, LiCoO 2 , widely used as cathode in lithium ion batteries was synthesized and their structural and electronic properties investigated. The crystalline powders were prepared by the sol-gel method with four complexing agents: citric acid, glycine, starch and gelatin. These syntheses were compared with the blank test (without complexing agent). The X-ray diffraction and vibrational spectroscopy allowed the identification of the rhombohedral phase LiCoO 2 ( ) as the only or principal crystalline component in all samples. A small fraction of a second phase of cubic spinel Co 3 O 4 was observed in the samples of starch, gelatin and the blank test. The Rietveld refinements showed small structural variations, indicating reduced influence of the complexing agents on the synthesis. The theoretical HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gap values are in agreement to those estimated by diffuse reflectance spectroscopy (DRS). The scanning electron microscopy (SEM) showed morphological pattern regardless of the complexing agent used, showing an alternative method.Keywords: LiCoO 2 , sol-gel method, XRD, Rietveld refinement, lithium ion batteries, DFT IntroductionLithium cobalt oxide, LiCoO 2 , has been the focus of many studies regarding their structural and electronic properties. [1][2][3][4][5][6][7][8] This system has interesting electrochemical features that allows a wide use as cathodes of lithium ion batteries. 2,4 The investigation of the structural aspects of the material is a crucial issue to better understand the electrochemical properties of the LiCoO 2 compound. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For example, the nature of the crystal, its size and shape, are directly related with its electrochemical characteristics. 2 The LiCoO 2 synthesized at low temperatures (LT), below 500 °C, presents a cubic spinel structure ( ), while the synthesis at high temperatures (HT) (above 500 °C), generates the rhombohedral structure with stratified layers ( ). Therefore, several authors usually classify these structures as LT-LiCoO 2 and HT-LiCoO 2 , respectively . 1,2,7,8,[18][19][20][21][22][23][24] The rhombohedral phase is characterized by a structure with alternating layers of cobalt and lithium cations intercalated with oxygen anions. 22 The lithium and cobalt(III) ions are arranged in intercalated layers (Figure 1a). The cobalt(III) ion is located at the octahedral sites, forming a strong bond with the neighboring oxygen anion to constitute the Co−O layers (Figure 1b). Finally, the lithium layers are intercalated between the CoO 2 plans. 1,3,4 The octahedral sites of these layers are occupied by lithium and cobalt(III) ions alternately that forms a sequential stacking with oxygen ion layers in a close packing of the ABCABC type ( Figure 1c). 4,5 This specific stacking arrangement leads to an environment equivalent for all ions, allowing the maximum charge delocalization and the minimal system energy. 1,3,4 The degree of crystal orde...

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Cation Migration-Induced Crystal Phase Transformation in Copper Ferrite Nanoparticles and Their Magnetic Property

Cited by 62 publications

References 47 publications

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

NiFe₂O₄nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

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Cation Migration-Induced Crystal Phase Transformation in Copper Ferrite Nanoparticles and Their Magnetic Property

Cited by 62 publications

References 47 publications

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

Effect of Molybdenum Incorporation on the Structure and Magnetic Properties of Cobalt Ferrite

NiFe2O4nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

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NiFe₂O₄nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions