Improved magnetic properties and growth anisotropy of chemically modified Sr ferrites

Jung W. Lee, Yong Soo Cho, Vasantha R.W. Amarakoon

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Abstract

Magnetic properties and microstructural characteristics of SrO·5.9Fe2O3 chemically modified with Si and Ca were investigated by changing experimental parameters such as additive composition, the ratio of Ca/Si, and sintering condition. A novel particulate coating method utilizing sol-gel reactions was used to uniformly incorporate the additives of Si and Ca. This method was very successful in obtaining homogeneous grain growth and fine grains. A sample containing the gel additives of 0.6 wt% SiO2 and 0.7 wt% CaO and sintered at 1200°C for 4 h was found to significantly suppress abnormal grain growth, resulting in submicron-sized grains and high density. A distinct grain boundary phase containing Si and Ca was observed by increasing the sintering temperature to 1250°C. The resultant microstructural characteristics favorably affected magnetic properties. For example, the chemically modified sample exhibited a higher coercivity of 3530 Oe compared to a value of 2050 Oe obtained for the sample without the additives. On the other hand, an increase in the ratio of Ca/Si or in sintering temperature tended to induce a large anisotropy during grain growth.

Original languageEnglish
Pages (from-to)5696-5698
Number of pages3
JournalJournal of Applied Physics
Volume85
Issue number8 II B
Publication statusPublished - 1999 Apr 15

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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