Sol–gel synthesis and anomalous magnetic behaviour of NiO nanoparticles

Thota, Subhash; Kumar, Jitendra

doi:10.1016/j.jpcs.2007.06.010

Cited by 164 publications

(79 citation statements)

References 47 publications

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“…These results suggest that there are two possible components associated with the magnetization reversal process: (i) an easily magnetizing component at low-field region and (ii) a non-saturating component responsible for almost linear variation in the high-field region. 9,23 In order to separate these two components, the field dependent magnetization curves were analysed using eqn. (2)…”

Section: Magnetic Propertiesmentioning

confidence: 99%

“…18 Extensive studies have been reported over a last decade on particle size dependent magnetic properties [10][11][12] and finite size versus surface effects on magnetic properties, 19 effect of substitution, 20 and room temperature magnetic crossover [21][22][23][24] of NiO prepared by various techniques. A combined experimental and computation study carried out by Yi et al showed a remarkable size-dependent magnetism with large magnetization of 105 emu/g and ferromagnetic ordering temperature of 35 K, when the size of the NiO cluster is about 1 nm.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

2015

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We report systematic investigations of structural, vibrational, resonance and magnetic properties of nanoscale NiO powders prepared by ball milling process under different milling speeds for 30 hours of milling. Structural properties revealed that both pure NiO and as-milled NiO powders exhibit face centered cubic structure, but average crystallite size decreases to around 11 nm along with significant increase in strain with increasing milling speed. Vibrational properties show the enhancement in the intensity of one-phonon longitudinal optical (LO) band and disappearance of two-magnon band due to size reduction. In addition, two-phonon LO band exhibits red shift due to size-induced phonon confinement effect and surface relaxation. Pure NiO powder exhibit antiferromagnetic nature, which transforms into induced ferromagnetic after size reduction. The average magnetization at room temperature increases with decreasing the crystallite size and a maximum moment of 0.016 μB/f.u. at 12 kOe applied field and coercivity of 170 Oe were obtained for 30 hours milled NiO powders at 600 rotation per minute milling speed. The change in the magnetic properties is also supported by the vibrational properties. Thermomagnetization measurements at high temperature reveal a well-defined magnetic phase transition at high temperature (TC) around 780 K due to induced ferromagnetic phase. Electron paramagnetic resonance (EPR) studies reveal a good agreement between the EPR results and magnetic properties. The observed results are described on the basis of crystallite size variation, defect density, large strain, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. The obtained results suggest that nanoscale NiO powders with high TC and moderate magnetic moment at room temperature with cubic structure would be useful to expedite for spintronic devices.

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Section: Magnetic Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

2015

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“…For example, calcination of precursors such as nickel oxalate dihydrate [34], nickel citrate [35], and nickel carbonate hydroxide [36] : 350-650 1C). However, NiO nanocrystallites of very small size ($2-6 nm) are difficult to obtain by the method of variation in heat treatment conditions.…”

Section: Article In Pressmentioning

confidence: 99%

The effect of anion on the magnetic properties of nanocrystalline NiO synthesized by homogeneous precipitation

Pulimi

Jeevanandam

2009

Journal of Magnetism and Magnetic Materials

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“…Recently, efforts have been placed to develop, characterize and describe the physio-chemical properties of NiO nanostructures. NiO has a number of intensive applications generally a pure material for specialty applications and metallurgical grade; mainly used for the manufacturing of alloys, frits, ferrites, porcelain glazes [2,3], magnetic materials [4], alkaline batteries cathode [5], anode material for Li-ion batteries [6,7], gas sensors [8], anti-ferromagnetic layers [9], solid-oxide fuel cells [10,11], drug delivery and magnetic resonance imaging (MRI) [12]. NiO use in nanoscale optoelectronics devices such as electrochromic display optical fibers, photovoltaic applications [13,14], p-n heterojunctions [15], catalysis [16,17], the electrode material for electrochemical capacitors, [18] and smart windows [19].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Pyramid-Shaped NiO Nanostructures using Low-Temperature Composite- Hydroxide- Mediated Approach

Shahid¹,

Khan²,

Zakria³

et al. 2016

J Material Sci Eng

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Composite-hydroxide-mediated (CHM) approach was used to synthesize NiO nanocrystals. The proposed method makes use of molten composite hydroxides; providing reaction media and lower the process temperature. Processing temperature and reaction time are the two potential parameters to control the growth of a nanomaterial. The method was used at temperatures in the range of 180-250°C and formation of the nanomaterial was monitored using XRD, SEM, EDX, FTIR, and UV-visible spectroscopy. The produced nanomaterial was purely polycrystalline with an average crystallite size in the range of 23.71-36.92 nm. Method suggested formation of pyramid shaped NiO nanocrystals in the temperature range 220-250°C. Evidence on the elemental composition, purity, and chemical bonding were obtained from EDX and FTIR analysis respectively. Estimation on direct bandgap was made from the optical analysis and found to be in the range 4.0-4.8 eV. The method is attractive and seems a cost effective route for the growth of transition metal oxides for research purpose. For further efficacy, the approach can be examined for other technologically significant nanostructures.

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Sol–gel synthesis and anomalous magnetic behaviour of NiO nanoparticles

Cited by 164 publications

References 47 publications

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

The effect of anion on the magnetic properties of nanocrystalline NiO synthesized by homogeneous precipitation

Synthesis of Pyramid-Shaped NiO Nanostructures using Low-Temperature Composite- Hydroxide- Mediated Approach

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