NISHA SHANKHWAR

Dr. NISHA SHANKHWAR

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India
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Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 May 2015 in Journal of Applied Physics
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Journal Article
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PKPawan Kumar
Pawan Kumar
NSNISHA SHANKHWAR
NISHA SHANKHWAR
ASA. Srinivasan
A. Srinivasan
MKManoranjan Kar
Manoranjan Kar
The co-doping of Ca and Mn in respective Bi and Fe-sites of BiFeO3 lattice leads to structural transition from rhombohedral (R3c space group) to orthorhombic (Pbnm space group) crystal symmetry. The tilt angle for anti-phase rotation of the oxygen octahedra of BiFeO3 at room temperature is observed to be ∼13.8°. It decreases with the increase in the co-doping percentage which suggests the composition-driven structural phase transition. The remnant magnetization for sample with 15% of co-doping becomes about 16 times that of BiFeO3. It may be attributed to the suppression of cycloid spin structure and uncompensated spins at the surface of nanocrystallites. Further increase in co-doping percentage results in the sharp reduction of remnant magnetization due to the dominant contribution from the collinear antiferromagnetic ordering in the Pbnm space group. The Arrott plot analysis clearly indicates the composition-driven crossover from the antiferromagnetic to weak ferromagnetic ordering and vice versa. Electron spin resonance results provide the evidence for the composition-driven phase transitions from an incommensurate spin cycloidal modulated state to one with nearly homogeneous spin order. The band gap (2.17 eV) of BiFeO3 measured using UV-Vis spectra was supported by the resonance Raman spectra.

1 May 2016 in Materials Science and Engineering: C
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Journal Article
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NSNISHA SHANKHWAR
NISHA SHANKHWAR
ASA. Srinivasan
A. Srinivasan

23 December 2015 in Journal of Biomaterials Science, Polymer Edition
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Journal Article
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NSNISHA SHANKHWAR
NISHA SHANKHWAR
MKManishekhar Kumar
Manishekhar Kumar
BMBiman B. Mandal
Biman B. Mandal
PRP. S. Robi
P. S. Robi
ASA. Srinivasan
A. Srinivasan
Cross-linked polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) composite nanofibrous membranes have been prepared by electrospinning. Mechanical properties of the membranes improved significantly with PVP addition. PVP improved hydrophilicity and sustainable degradation of the membranes. Biocompatibility of the membranes was assessed by in vitro culture of native skin cells (L929 fibroblast and HaCaT keratinocytes). Tests showed sustained release of the antibiotic ciprofloxacin hydrochloride monohydrate by the membranes. Further, zone of inhibition study against Staphylococcus aureus growth demonstrated protective action against external pathogenic microbes. These studies show these simple PVA–PVP nanofibrous membranes are promising interactive antibiotic-eluting wound dressing materials.

1 December 2016 in Materials Science and Engineering: C
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Journal Article
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NSNISHA SHANKHWAR
NISHA SHANKHWAR
MKManishekhar Kumar
Manishekhar Kumar
BMBiman B. Mandal
Biman B. Mandal
ASA. Srinivasan
A. Srinivasan

23 December 2013 in IEEE Transactions on Magnetics
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NSNISHA SHANKHWAR
NISHA SHANKHWAR
RSRajendra K. Singh
Rajendra K. Singh
GKG. P. Kothiyal
G. P. Kothiyal
APA. Perumal
A. Perumal
ASA. Srinivasan
A. Srinivasan
Magnetic hysteresis loss and the resulting local heating in implanted thermoseed (magnetic biocompatible material) can be used to selectively destroy cancerous tissue. We have prepared magnetic bioglass ceramics (MBC) by annealing 41CaO·44 SiO 2 ·4P 2 O 5 ·8Fe 2 O 3 ·3Na 2 O glass at temperatures ( TA) ranging from 750 ° C to 1150 ° C for 1 h. X-ray diffraction patterns confirm the presence of bone mineral (hydroxyapatite and wollastonite) and magnetite ( Fe 3 O 4 ) phases in nanocrystalline form in the MBCs. Average crystallite size ( d av ) of all the phases increased with increasing T A . Magnetization ( M-H) curves of all MBCs were recorded up to 20 kOe at 300 K to understand the evolution of magnetism in the nonmagnetic glass upon heat treatment. Magnetic properties correlated with d av(magnetite) for samples annealed up to 1050 ° C. Electron paramagnetic resonance study was carried out to understand the behavior of sample annealed at 1150 ° C and the evolution of magnetic properties in the MBCs. This study also reveals a methodology to control the magnetic properties of this MBC and its potential application in hyperthermia treatment of bone cancer.

1 September 2014 in Physica B: Condensed Matter
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Journal Article
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NSNISHA SHANKHWAR
NISHA SHANKHWAR
GKG.P. Kothiyal
G.P. Kothiyal
ASA. Srinivasan
A. Srinivasan