Magnetic studies of SiO2 coated CoFe2O4 nanoparticles

Mukta V. Limaye; Shashi B. Singh; Raja Das; Pankaj Poddar; Majid K. Abyaneh; Sulabha K. Kulkarni

doi:10.1016/j.jmmm.2017.06.061

Magnetic studies of SiO₂ coated CoFe₂O₄ nanoparticles

Mukta V. Limaye, Shashi B. Singh, Raja Das, Pankaj Poddar, Majid K. Abyaneh, Sulabha K. Kulkarni

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

Oleic acid capped CoFe₂O₄ nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO₂. We have used chemical synthesis method to obtain SiO₂ coated CoFe₂O₄ nanoparticles with different weight percentages of CoFe₂O₄ in SiO₂ (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe₂O₄ nanoparticles is retained after silica coating process. The complete coating of SiO₂ on CoFe₂O₄ nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO₂ coated CoFe₂O₄ particles remains more or less unaffected as in CoFe₂O₄ nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe₂O₄ and SiO₂ coated 1.5 wt.% CoFe₂O₄ samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe₂O₄ nanoparticles.

Original language	English
Pages (from-to)	683-690
Number of pages	8
Journal	Journal of Magnetism and Magnetic Materials
Volume	441
DOIs	https://doi.org/10.1016/j.jmmm.2017.06.061
Publication status	Published - 01 Nov 2017
Externally published	Yes

Keywords

Chemical synthesis
Magnetic materials
Photoelectron spectroscopy

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10.1016/j.jmmm.2017.06.061

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@article{e21e50defc9e4f62a506f961d91e137e,

title = "Magnetic studies of SiO2 coated CoFe2O4 nanoparticles",

abstract = "Oleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.",

keywords = "Chemical synthesis, Magnetic materials, Photoelectron spectroscopy",

author = "Limaye, {Mukta V.} and Singh, {Shashi B.} and Raja Das and Pankaj Poddar and Abyaneh, {Majid K.} and Kulkarni, {Sulabha K.}",

note = "Funding Information: MVL and SBS thank to Department of Science and Technology (DST), India for financial support under DST-INSPIRE Faculty scheme. The authors would like to thank Dr. Vasant Sathe and late Dr. S. K. Date for Raman measurements and for valuable suggestions respectively. The authors would like to thank Department of Physics, University of Pune for experimental facilities. P.P. and R. D. acknowledge the funding from the ?Department of Science and Technology, India (DST)? through the grant no. SR/S5/NM-104/2006 under the ?Nano Mission? program. Publisher Copyright: {\textcopyright} 2017 Elsevier B.V.",

year = "2017",

month = nov,

day = "1",

doi = "10.1016/j.jmmm.2017.06.061",

language = "English",

volume = "441",

pages = "683--690",

journal = "Journal of Magnetism and Magnetic Materials",

issn = "0304-8853",

publisher = "Elsevier",

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TY - JOUR

T1 - Magnetic studies of SiO2 coated CoFe2O4 nanoparticles

AU - Limaye, Mukta V.

AU - Singh, Shashi B.

AU - Das, Raja

AU - Poddar, Pankaj

AU - Abyaneh, Majid K.

AU - Kulkarni, Sulabha K.

N1 - Funding Information: MVL and SBS thank to Department of Science and Technology (DST), India for financial support under DST-INSPIRE Faculty scheme. The authors would like to thank Dr. Vasant Sathe and late Dr. S. K. Date for Raman measurements and for valuable suggestions respectively. The authors would like to thank Department of Physics, University of Pune for experimental facilities. P.P. and R. D. acknowledge the funding from the ?Department of Science and Technology, India (DST)? through the grant no. SR/S5/NM-104/2006 under the ?Nano Mission? program. Publisher Copyright: © 2017 Elsevier B.V.

PY - 2017/11/1

Y1 - 2017/11/1

N2 - Oleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.

AB - Oleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.

KW - Chemical synthesis

KW - Magnetic materials

KW - Photoelectron spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85021168788&partnerID=8YFLogxK

U2 - 10.1016/j.jmmm.2017.06.061

DO - 10.1016/j.jmmm.2017.06.061

M3 - Article

AN - SCOPUS:85021168788

VL - 441

SP - 683

EP - 690

JO - Journal of Magnetism and Magnetic Materials

JF - Journal of Magnetism and Magnetic Materials

SN - 0304-8853

ER -

Magnetic studies of SiO₂ coated CoFe₂O₄ nanoparticles

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Keywords

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