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Title: Structural, optical, hyperfine and magnetization studies of ZnO encapsulated α-Fe nanoparticles

We report the successful preparation and characterization of magnetic-fluorescent nanoparticles (NPs) by overcoming the difficulty of handling α-Fe nanoparticles that are less stable and have high affinity to get oxidized in air even at room temperature. Nanocrystalline α-Fe particles embedded by ZnO have been synthesized by a two step chemical route. Concentration of α-Fe has been varied as 15, 30 and 50 wt% of the sample. Detailed investigations on structural, hyperfine, optical and magnetic characteristics have been carried out. X-ray diffraction, transmission electron microscopy and fourier transform infrared spectroscopy studies have been used to confirm the coexistence of Fe and ZnO phases in the nanocomposites (NCs). The presence of α-Fe is also confirmed by Mössbauer spectroscopy. However, other forms of iron are also detected in the sample. UV–vis spectrum of nanocomposites shows a red shift with respect to the pristine ZnO which is attributed to the electron transfer between Fe and ZnO that provides support to the formation of the Fe- ZnO NC. The photoluminescence (PL) spectra of Fe-ZnO nanocomposites exhibit blue shift of the UV and weaker visible emission lines compared to the pristine ZnO. Nanocomposites are found to be magnetically soft having high saturation magnetization with very lowmore » remanence. Low temperature coercivity enhancement due to freezing of uncompensated surface spins is also found in all samples.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [3] ;  [5] ;  [3]
  1. UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India)
  2. (India)
  3. UGC-DAE Consortium for Scientific Research, III/LB-8, Bidhannagar, Kolkata 700098 (India)
  4. (Japan)
  5. Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India)
Publication Date:
OSTI Identifier:
22420699
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 60; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; COERCIVE FORCE; CONCENTRATION RATIO; CRYSTALS; FLUORESCENCE; IRON; MAGNETIZATION; NANOCOMPOSITES; NANOPARTICLES; NANOSTRUCTURES; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; RED SHIFT; SYNTHESIS; TEMPERATURE DEPENDENCE; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; ZINC OXIDES