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Title: Effects of heat treatment and magnetoannealing on nanocrystalline Co-ferrite powders

Abstract

This work consists of three parts: the effects of heat treatment (slow cooling and quenching), magnetoannealing, and postannealing of samples with induced anisotropy. It has been found that noncomplete inverse spinel structure was the result after annealing at higher temperature and quenching. Our Moessbauer spectroscopy study confirmed noncomplete inverse structure after quenching, while inverse spinel structure was formed after slow cooling. The kinetics of the formation of induced anisotropy during magnetoannealing has been investigated in this study. Reduction of crystalline magnetic anisotropy was observed, as coercivity decreased after magnetoannealing. The change of remanence ratio and coercivity followed the expected equations for ion diffusion. A relative large anisotropy in magnetization was evident. A postannealing resulted in the conversion into the initial isotropic stage. The process could be well described using the equations of ion diffusion.

Authors:
; ; ; ; ;  [1]
  1. Department of Materials Science and Engineering, National University of Singapore, Singapore 119260 (Singapore)
Publication Date:
OSTI Identifier:
20787730
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 98; Journal Issue: 12; Other Information: DOI: 10.1063/1.2148632; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ANNEALING; COBALT COMPOUNDS; COERCIVE FORCE; COOLING; CRYSTALS; EQUATIONS; FERRITES; IONIC CONDUCTIVITY; MAGNETIZATION; MOESSBAUER EFFECT; NANOSTRUCTURES; POWDERS; QUENCHING; REACTION KINETICS; SPINELS

Citation Formats

Wang, Y.C., Ding, J., Yin, J.H., Liu, B.H., Yi, J.B., and Yu, S.. Effects of heat treatment and magnetoannealing on nanocrystalline Co-ferrite powders. United States: N. p., 2005. Web. doi:10.1063/1.2148632.
Wang, Y.C., Ding, J., Yin, J.H., Liu, B.H., Yi, J.B., & Yu, S.. Effects of heat treatment and magnetoannealing on nanocrystalline Co-ferrite powders. United States. doi:10.1063/1.2148632.
Wang, Y.C., Ding, J., Yin, J.H., Liu, B.H., Yi, J.B., and Yu, S.. Thu . "Effects of heat treatment and magnetoannealing on nanocrystalline Co-ferrite powders". United States. doi:10.1063/1.2148632.
@article{osti_20787730,
title = {Effects of heat treatment and magnetoannealing on nanocrystalline Co-ferrite powders},
author = {Wang, Y.C. and Ding, J. and Yin, J.H. and Liu, B.H. and Yi, J.B. and Yu, S.},
abstractNote = {This work consists of three parts: the effects of heat treatment (slow cooling and quenching), magnetoannealing, and postannealing of samples with induced anisotropy. It has been found that noncomplete inverse spinel structure was the result after annealing at higher temperature and quenching. Our Moessbauer spectroscopy study confirmed noncomplete inverse structure after quenching, while inverse spinel structure was formed after slow cooling. The kinetics of the formation of induced anisotropy during magnetoannealing has been investigated in this study. Reduction of crystalline magnetic anisotropy was observed, as coercivity decreased after magnetoannealing. The change of remanence ratio and coercivity followed the expected equations for ion diffusion. A relative large anisotropy in magnetization was evident. A postannealing resulted in the conversion into the initial isotropic stage. The process could be well described using the equations of ion diffusion.},
doi = {10.1063/1.2148632},
journal = {Journal of Applied Physics},
number = 12,
volume = 98,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
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