Navya Joseph, Surya Gopi, Aladin Ullrich, Manfred Albrecht, Senoy Thomas
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引用次数: 0
摘要
采用不同尿素浓度的 FeCl3-6H2O 强制水解法制备了细长的阿卡干纳石（β-FeOOH）纳米粒子。观察发现，β-FeOOH 在温度诱导下转化为γ-Fe2O3，随后又转化为ϵ-Fe2O3。由于ϵ-Fe2O3 相的形成，在 900 °C 下退火的样品的矫顽力迅速增加到 16 kOe，在 1200 °C 下退火的样品的矫顽力达到 21.5 kOe。在 1300 ℃ 的较高温度下，ϵ-Fe2O3 相主要转变为α-Fe2O3 相，从而导致矫顽力迅速下降到可以忽略不计的值。
Formation of the hard-magnetic epsilon iron oxide phase from akaganéite nanoparticles.
Elongated akaganéite (β-FeOOH) nanoparticles were prepared by a forced hydrolysis route using FeCl3·6H2O employing various urea concentrations.β-FeOOH nanoparticles stabilized within the SiO2matrix were annealed at different temperatures, ranging from 500 °C to 1300 °C. It was observed thatβ-FeOOH underwent a temperature-induced conversion toγ-Fe2O3and subsequently toϵ-Fe2O3. Due to theϵ-Fe2O3phase formation, the coercivity rapidly increased to 16 kOe for samples annealed at 900 °C and reached values up to 21.5 kOe when annealed at 1200 °C. At a higher temperature of 1300 °C, theϵ-Fe2O3phase transforms mainly into theα-Fe2O3phase, which causes the coercivity to rapidly drop to negligible values.
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The journal aims to publish papers at the forefront of nanoscale science and technology and especially those of an interdisciplinary nature. Here, nanotechnology is taken to include the ability to individually address, control, and modify structures, materials and devices with nanometre precision, and the synthesis of such structures into systems of micro- and macroscopic dimensions such as MEMS based devices. It encompasses the understanding of the fundamental physics, chemistry, biology and technology of nanometre-scale objects and how such objects can be used in the areas of computation, sensors, nanostructured materials and nano-biotechnology.
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