Effects of the unique shape of submicron magnetite hollow spheres on magnetic properties and domain states
Effects of the unique shape of submicron magnetite hollow spheres on magnetic properties and domain states
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DOI：
10.1103/physrevb.75.224404
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发表时间：
2007-06
影响因子：
3.7
通讯作者：
Q. Ye;Y. Kozuka;Hirofumi Yoshikawa;K. Awaga;S. Bandow;S. Iijima
中科院分区：
文献类型：
--
作者：
Q. Ye;Y. Kozuka;Hirofumi Yoshikawa;K. Awaga;S. Bandow;S. Iijima
采用模板法制备了亚微米级磁性空心球。得到的颗粒大小非常均匀，直径为1 mm，壳层厚度为1 mm。零场冷却磁化强度的温度依赖关系表明，在该温度范围内有一个广泛的反常现象，可归因于Verwey转变，而通过研磨空心球体得到的磁铁矿纳米颗粒在这个温度范围内没有反常现象。尤其是在Verwey转变温度以下，空心球的矫顽场比纳米级和块状磁铁矿的更显著。白天的情节[物理。地球星球。国际米兰。13,260(1977)]表明，在低温下，它们的磁畴状态类似于单磁畴状态。
Submicron-scale magnetitehollow spheres were prepared by a template method using polystyrene beads. The obtained particles were very uniform in size with a diameter ofand a shell thickness of. The temperature dependence of the zero-field cooled magnetizations indicated a broad anomaly at aroundthat was ascribable to the Verwey transition, while the magnetite nanoparticles, obtained by grinding the hollow spheres, exhibited no anomalies in this temperature range. Particularly below the Verwey transition temperature, the coercive fields of the hollow spheres increased much more significantly than did those of nanoscale and bulk magnetite. The Day plots [Phys. Earth Planet. Inter. 13, 260 (1977)] for the submicron hollow spheres indicated that their domain states were similar to the single-domain state at low temperature.