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Title: Pure dipolar-interacted CoFe{sub 2}O{sub 4} nanoparticles and their magnetic properties

Abstract

Graphical abstract: The mono-dispersed CoFe{sub 2}O{sub 4} nanoparticles with the uniform size of 10.5 ± 2 nm were first synthesized and then they were embedded in amorphous SiO{sub 2} matrix with different CoFe{sub 2}O{sub 4} nanoparticles’ concentrations. The large coercivity (3056 Oe) and the remanence ratio (0.63) were obtained by suitably diluting CoFe{sub 2}O{sub 4} nanoparticles into the SiO{sub 2} matrix. The reciprocal of the absolute maximum of δm and the M{sub r}/M{sub s} ratio behave in the same trend (as shown in (e)), indicating that the M{sub r}/M{sub s} ratio was dominated by the interparticle dipolar interaction. The present work is meaningful for revealing the underlying mechanism in nano-scaled magnetic system and improving the magnetic performance. - Highlights: • The mono-dispersed CoFe{sub 2}O{sub 4} nanoparticles with the uniform size of 10.5 ± 2 nm were synthesized by the thermal decomposition of metals acetylacetonates in solvents with high boiling point. • The large coercivity (3056 Oe) and the remanence ratio (0.63) were obtained by diluting CoFe{sub 2}O{sub 4} nanoparticles into the SiO{sub 2} matrix with a suitable concentration. • The surface anisotropy and interparticle dipolar interaction affect the magnetic performance and magnetic ordering state. • It was observed that themore » M{sub r}/M{sub s} ratio was dominated by the interparticle dipolar interaction. - Abstract: The mono-dispersed and uniform CoFe{sub 2}O{sub 4} nanoparticles were synthesized by the thermal decomposition of Fe(acac){sub 3} and Co(acac){sub 2}. Then the CoFe{sub 2}O{sub 4} nanoparticles were diluted in amorphous SiO{sub 2} matrix with different CoFe{sub 2}O{sub 4} nanoparticles’ concentrations. All samples show the positive or negative exchange bias behavior, indicating the presence of canted spin layer at the CoFe{sub 2}O{sub 4} nanoparticles’ surface. The large effective anisotropy constant (3.38 × 10{sup 6} erg/cm{sup 3}) was observed, which can be attributed to the induced surface anisotropy by the canted surface spins. The reduced magnetization (M{sub r}/M{sub s}) was dominated by the interparticle dipolar interaction while the coercivity (H{sub c}) was determined by the synergistic effects of the surface anisotropy, interparticle dipolar interaction and interface effect. By suitably diluting CoFe{sub 2}O{sub 4} in the SiO{sub 2} matrix, the high H{sub c} (3056 Oe) and the M{sub r}/M{sub s} (0.63) can be obtained, which is larger than most of those reported before. The present work is meaningful for revealing the underlying mechanism in nano-scaled magnetic system and improving the magnetic performance.« less

Authors:
 [1];  [1]; ; ; ; ;  [1]
  1. Anhui Key Laboratory of Information Materials and Devices, School of Physics and Materials Science, Anhui University, Hefei 230039 (China)
Publication Date:
OSTI Identifier:
22420809
Resource Type:
Journal Article
Journal Name:
Materials Research Bulletin
Additional Journal Information:
Journal Volume: 62; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0025-5408
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; BOILING POINTS; COBALT OXIDES; COERCIVE FORCE; CONCENTRATION RATIO; INTERFACES; IRON OXIDES; LAYERS; MAGNETIC MATERIALS; MAGNETIC PROPERTIES; MAGNETIZATION; NANOPARTICLES; PYROLYSIS; SILICON OXIDES; SPIN; SURFACES; SYNTHESIS

Citation Formats

Xu, Shi-tao, School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Ma, Yong-qing, Xu, Yuan-feng, Sun, Xiao, Geng, Bing-qian, Zheng, Gan-hong, and Dai, Zhen-xiang. Pure dipolar-interacted CoFe{sub 2}O{sub 4} nanoparticles and their magnetic properties. United States: N. p., 2015. Web. doi:10.1016/J.MATERRESBULL.2014.11.005.
Xu, Shi-tao, School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Ma, Yong-qing, Xu, Yuan-feng, Sun, Xiao, Geng, Bing-qian, Zheng, Gan-hong, & Dai, Zhen-xiang. Pure dipolar-interacted CoFe{sub 2}O{sub 4} nanoparticles and their magnetic properties. United States. https://doi.org/10.1016/J.MATERRESBULL.2014.11.005
Xu, Shi-tao, School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Ma, Yong-qing, Xu, Yuan-feng, Sun, Xiao, Geng, Bing-qian, Zheng, Gan-hong, and Dai, Zhen-xiang. 2015. "Pure dipolar-interacted CoFe{sub 2}O{sub 4} nanoparticles and their magnetic properties". United States. https://doi.org/10.1016/J.MATERRESBULL.2014.11.005.
@article{osti_22420809,
title = {Pure dipolar-interacted CoFe{sub 2}O{sub 4} nanoparticles and their magnetic properties},
author = {Xu, Shi-tao and School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 and Ma, Yong-qing and Xu, Yuan-feng and Sun, Xiao and Geng, Bing-qian and Zheng, Gan-hong and Dai, Zhen-xiang},
abstractNote = {Graphical abstract: The mono-dispersed CoFe{sub 2}O{sub 4} nanoparticles with the uniform size of 10.5 ± 2 nm were first synthesized and then they were embedded in amorphous SiO{sub 2} matrix with different CoFe{sub 2}O{sub 4} nanoparticles’ concentrations. The large coercivity (3056 Oe) and the remanence ratio (0.63) were obtained by suitably diluting CoFe{sub 2}O{sub 4} nanoparticles into the SiO{sub 2} matrix. The reciprocal of the absolute maximum of δm and the M{sub r}/M{sub s} ratio behave in the same trend (as shown in (e)), indicating that the M{sub r}/M{sub s} ratio was dominated by the interparticle dipolar interaction. The present work is meaningful for revealing the underlying mechanism in nano-scaled magnetic system and improving the magnetic performance. - Highlights: • The mono-dispersed CoFe{sub 2}O{sub 4} nanoparticles with the uniform size of 10.5 ± 2 nm were synthesized by the thermal decomposition of metals acetylacetonates in solvents with high boiling point. • The large coercivity (3056 Oe) and the remanence ratio (0.63) were obtained by diluting CoFe{sub 2}O{sub 4} nanoparticles into the SiO{sub 2} matrix with a suitable concentration. • The surface anisotropy and interparticle dipolar interaction affect the magnetic performance and magnetic ordering state. • It was observed that the M{sub r}/M{sub s} ratio was dominated by the interparticle dipolar interaction. - Abstract: The mono-dispersed and uniform CoFe{sub 2}O{sub 4} nanoparticles were synthesized by the thermal decomposition of Fe(acac){sub 3} and Co(acac){sub 2}. Then the CoFe{sub 2}O{sub 4} nanoparticles were diluted in amorphous SiO{sub 2} matrix with different CoFe{sub 2}O{sub 4} nanoparticles’ concentrations. All samples show the positive or negative exchange bias behavior, indicating the presence of canted spin layer at the CoFe{sub 2}O{sub 4} nanoparticles’ surface. The large effective anisotropy constant (3.38 × 10{sup 6} erg/cm{sup 3}) was observed, which can be attributed to the induced surface anisotropy by the canted surface spins. The reduced magnetization (M{sub r}/M{sub s}) was dominated by the interparticle dipolar interaction while the coercivity (H{sub c}) was determined by the synergistic effects of the surface anisotropy, interparticle dipolar interaction and interface effect. By suitably diluting CoFe{sub 2}O{sub 4} in the SiO{sub 2} matrix, the high H{sub c} (3056 Oe) and the M{sub r}/M{sub s} (0.63) can be obtained, which is larger than most of those reported before. The present work is meaningful for revealing the underlying mechanism in nano-scaled magnetic system and improving the magnetic performance.},
doi = {10.1016/J.MATERRESBULL.2014.11.005},
url = {https://www.osti.gov/biblio/22420809}, journal = {Materials Research Bulletin},
issn = {0025-5408},
number = ,
volume = 62,
place = {United States},
year = {Sun Feb 15 00:00:00 EST 2015},
month = {Sun Feb 15 00:00:00 EST 2015}
}