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Title: Semiconductor-to-metallic flipping in a ZnFe{sub 2}O{sub 4}–graphene based smart nano-system: Temperature/microwave magneto-dielectric spectroscopy

Zn-(FeO{sub 2}){sub 2}–graphene smart nano-composites were synthesized using a novel modified solvothermal synthesis with different percentages of graphene. The structure of the nanocomposite was confirmed through X-ray diffraction, micro-Raman scattering spectroscopy, Ultraviolet–Visible spectroscopy, and Fourier transform infrared spectroscopy. The structural growth and morphological aspects were analyzed using scanning/transmission electron microscopy, revealing marvelous micro-structural features of the assembled nano-system resembling a maple leaf. To determine the composition, energy dispersive spectroscopy and X-ray photoelectron spectroscopy were used. Microwave magneto-dielectric spectroscopy revealed the improved dielectric properties of the nano-composite compared to those of the parent functional nanocrystals. Temperature gradient dielectric spectroscopy was used over the spectral range from 100 Hz to 5 MHz to reveal the phenomenological effect that the nanosystem flips from its usual semiconductor nature to a metallic nature with sensing temperature. Electrical conductivity and dielectric analysis indicated that the dielectric loss and the dielectric permittivity increased at room temperature. This extraordinary switching capability of the functionalized graphene nanosystem opens up a new dimension for engineering advanced and efficient smart composite materials. - Graphical abstract: Display Omitted - Highlights: • Zn-(FeO{sub 2}){sub 2}–graphene smart nano-composites were synthesized using a novel modified solvothermal synthesis. • The synthesized nano-system exhibits marvelous leaf likemore » microstructure. • These nano-composites show improved magneto dielectric response. • This engineered smart nano-system shows phenomenological flipping from semiconductor like nature to metallic behavior.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), H-12, Islamabad (Pakistan)
  2. Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China)
Publication Date:
OSTI Identifier:
22476023
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 99; 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:
77 NANOSCIENCE AND NANOTECHNOLOGY; CERAMICS; COMPOSITE MATERIALS; DIELECTRIC MATERIALS; ELECTRIC CONDUCTIVITY; FERRITES; FOURIER TRANSFORM SPECTROMETERS; GRAPHENE; IRON OXIDES; MICROSTRUCTURE; MICROWAVE RADIATION; NANOSTRUCTURES; PERMITTIVITY; RAMAN EFFECT; SEMICONDUCTOR MATERIALS; SYNTHESIS; TEMPERATURE GRADIENTS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY; ZINC COMPOUNDS