压力引发磁铁矿的磁阻率反转
Pressure induced magnetoresistivity reversal in magnetite
本文测量了纳米粉末状的磁铁矿（Fe3O4）在极端条件下的磁阻率，其中压力达到19.0 GPa，磁场达到15 kG。结果显示，当压力小于6.0 GPa时，磁铁矿呈现出奇特的准线性的正磁阻效应；在大约6.0 GPa时，磁阻效应开始由正的变为负的。低压下（压力小于6.0 GPa）的反常的正磁阻效应归因于Fe3O4样品具有高的负自旋极化率，这样Fe3O4样品和Mo电极接触面的纳米异质形成的高势垒会引起定域效应。磁阻效应在6.0 GPa发生反转是由于压力使得磁铁矿发生了由半金属到金属的相变。
he magnetoresistivity (MR) of nano-powdered magnetite has been measured under pressures up to 19.0 GPa and magnetic fields up to 15 kG. An unexpected quasi-linear positive MR below 6.0 GPa and an MR transition from positive to negative around 6.0 GPa have been found. The abnormal positive MR below 6.0 GPa originates from the confinement effect caused by nano-scale heterogeneity at the contact surface between Mo and Fe3O4 sample and the high negative spin polarization of magnetite. The MR transition at about 6.0 GPa comes from a phase transition from half-metal to metal induced by pressure.
彭刚、李玉强、刘才龙、李岩、苏宁宁、王庆林、韩永昊
物理学
金刚石对顶砧磁阻率高压
magnetoresistivitydiamond anvil cellhigh pressure
彭刚,李玉强,刘才龙,李岩,苏宁宁,王庆林,韩永昊.压力引发磁铁矿的磁阻率反转[EB/OL].(2012-01-10)[2025-05-15].http://www.paper.edu.cn/releasepaper/content/201201-305.点此复制
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