Influence of iron ions on the magnetic properties of CaO–SiO₂–P₂O₅–Na₂O–Fe₂O₃ glass–ceramics

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• 作者：Rajendra Kumar Singh ; G.P. Kothiyal ; A. Srinivasan
• 关键词：A. Magnetic material ; D. Superexchange ; E. Electron spin resonance ; E. Magnetometry
• 刊名：Solid State Communications
• 出版年：2008
• 期刊代码：101_00381098
• 类别：ms
• 出版时间：April 2008
• 卷：146
• 期：1-2
• 页码：25-29
• 文件大小：432 K

摘要

Room temperature Electron Paramagnetic Resonance (EPR) spectra and temperature dependent magnetic susceptibility measurements have been performed on 41CaO.(52−x)SiO₂.4P₂O₅.xFe₂O₃.3Na₂O (pan class="inlMMLBox">g src="http://www.sciencedirect.com/cache/MiamiImageURL/B6TVW-4RR1NV3-5-21/0?wchp=dGLbVzb-zSkWW" alt="View the MathML source" title="View the MathML source" align="absbottom" border="0" height=12 width="102"/>pan>) glass–ceramics. The parent glass samples were prepared by quenching the homogenized melt from 1550 p>g src="http://www.sciencedirect.com/scidirimg/entities/2218.gif" alt="ring operator" title="ring operator" border="0">p>C. The glasses were then heat-treated at 1050 p>g src="http://www.sciencedirect.com/scidirimg/entities/2218.gif" alt="ring operator" title="ring operator" border="0">p>C for 3 h and slowly cooled to room temperature to yield glass–ceramics. EPR and high temperature magnetic susceptibility measurements were made to elucidate the state of Fep>+3p> ions in the glass–ceramics. The EPR absorption line centered at g≈4.3 disappeared at higher concentrations of Fe₂O₃. The intensity and linewidth of the absorption line centered at g≈2.1 increased as the Fe₂O₃ concentration was increased. Information about the structural changes involving iron ions, their valence state and type of magnetic interactions between the Fe ions was obtained using EPR and magnetic susceptibility measurements. The temperature dependence of the magnetization of the glass–ceramics with low Fe₂O₃ concentrations exhibit both ferrimagnetic and paramagnetic contributions. The results obtained have been used to understand the structural changes occurring in the vicinity of iron ions and the nature of magnetic interactions between the iron ions in these glass–ceramics.