Visualized effect of oxidation on magnetic recording fidelity in pseudo-single-domain magnetite particles.
Visualized effect of oxidation on magnetic recording fidelity in pseudo-single-domain magnetite particles.
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DOI：
10.1038/ncomms6154
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发表时间：
2014-10-10
影响因子：
16.6
通讯作者：
Dunin-Borkowski, Rafal E.
中科院分区：
文献类型：
--
作者：
Almeida, Trevor P.;Kasama, Takeshi;Muxworthy, Adrian R.;Williams, Wyn;Nagy, Lesleis;Hansen, Thomas W.;Brown, Paul D.;Dunin-Borkowski, Rafal E.
磁铁矿（Fe3O4）是一种重要的磁性矿物，它在岩石中具有主要的磁特征，对其磁记录保真度的了解为古地磁研究提供了重要的工具。然而，随着时间的推移，Fe3O4颗粒的可靠记录保真度被逐渐氧化成磁性较低的氧化铁（如磁赤铁矿（γ-Fe2O3））而大大降低，从而导致剩余磁化强度的改变，可能具有重要的地质意义。在这里，我们使用环境透射电子显微镜和离轴电子全息术的互补技术来诱导和可视化氧化对单个纳米级Fe3O4颗粒向γ-Fe2O3转变时磁化的影响。磁感应图谱显示，在岩石中占主导地位的尺寸范围内，Fe3O4颗粒的剩余磁化强度和方向发生了变化，证实氧化可以改变原始存储的磁性信息。磁铁矿提供了地球地磁历史的宝贵记录。在这里，Almeida等人将电子显微镜和能量损失光谱相结合，研究了原位氧化对伪单畴磁铁矿晶粒磁化保真度和晶相的影响。
Magnetite (Fe3O4) is an important magnetic mineral to Earth scientists, as it carries the dominant magnetic signature in rocks, and the understanding of its magnetic recording fidelity provides a critical tool in the field of palaeomagnetism. However, reliable interpretation of the recording fidelity of Fe3O4 particles is greatly diminished over time by progressive oxidation to less magnetic iron oxides, such as maghemite (γ-Fe2O3), with consequent alteration of remanent magnetization potentially having important geological significance. Here we use the complementary techniques of environmental transmission electron microscopy and off-axis electron holography to induce and visualize the effects of oxidation on the magnetization of individual nanoscale Fe3O4 particles as they transform towards γ-Fe2O3. Magnetic induction maps demonstrate a change in both strength and direction of remanent magnetization within Fe3O4 particles in the size range dominant in rocks, confirming that oxidation can modify the original stored magnetic information. Magnetite provides a valuable record of the Earth's geomagnetic history. Here, Almeida et al. combine electron microscopy and energy-loss spectroscopy to study the effects of in situ oxidation on the magnetization fidelity and crystalline phase of pseudo-single domain magnetite grains.
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影响因子：
5.3
作者：
Kasama, Takeshi;Church, Nathan S.;Harrison, Richard J.
通讯作者：
Harrison, Richard J.
影响因子：
3.7
作者：
Chen, J;Huang, DJ;Chen, CT
通讯作者：
Chen, CT
影响因子：
3.7
作者：
Fujii, T;de Groot, FMF;Okada, K
通讯作者：
Okada, K
影响因子：
3.9
作者：
Feinberg, Joshua M.;Harrison, Richard J.;Renne, Paul R.
通讯作者：
Renne, Paul R.
影响因子：
2.8
作者：
McClelland, E
通讯作者：
McClelland, E