用溶胶-凝胶法制备了金红石Ti1-xCrxO2 (x=0、0.04、0.08)纳米粉末.磁性测量结果显示,制备的Cr掺杂金红石TiO2纳米粉末具有室温铁磁性,样品x=0.04和0.08的饱和磁化强度Ms分别为0.55×10-3和1.6×103 emu/g,(emu/g=4π×10-7Wb·m/kg)矫顽力Hc分别为220和40 Oe(Oe=103/(4π)A/m).Cr掺杂量较大的样品的饱和磁化强度较大,在Ar气中退火可以使粉末呈超顺磁性.Cr2p区域的密集扫描X射线光电子能谱(XPS)分析显示,在所有的样品中Cr都是以Cr3+存在.电子顺磁共振谱(EPR)分析表明,样品中的Cr3+离子仅对其顺磁性有贡献.这些结果提示,粉末微弱的室温铁磁性来源于掺杂引入的结构缺陷,其中,氧空位起重要作用.
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