磁铁矿粒径精细变化下的磁性特征研究

Study on Magnetic Characteristics of Magnetite with Fine Variation of Particles Size

在古地磁学研究中,精细粒径磁性样品中能否提取有效古地磁信息是古地磁学研究能否顺利开展的前提条件。基于这一问题,应用MERRILL软件对30 nm、60 nm、88 nm、150 nm截角八面体磁铁矿颗粒进行多次微磁模拟,发现:1)在常温下单畴(single domain,SD)、易轴指向单涡(easy-axis aligned single vortex,ESV)颗粒具有较高且稳定的矫顽力,而难轴指向单涡(hard-axis aligned single vortex,HSV)颗粒则存在波动;2)温度变化情况下,SD、ESV颗粒依旧保持较强的热稳定性,而HSV颗粒依旧存在波动。据此,推断SD结构与ESV结构磁铁矿颗粒可以作为古地磁学研究的良好信息载体。总之,该项研究在一定程度上拓宽了良好载磁颗粒的粒径范围,从而提高了有效古地磁信息的提取。

In paleomagnetic research,whether ethe paleomagnetic information can be extracted effectively from fine-grained magnetic samples is a prerequisite for the smooth progress of paleomagnetic research.Based on this problem,we used MERRILL software to simulate truncated octahedral magnetite particles at 30 nm,60 nm,88 nm,and 150 nm.We found that:1)SD and ESV particles have high and stable coercivity at room temperature,while HSV particles have magnetic fluctuations;2)SD and ESV particles still have strong thermal stability under temperature changes,while the HSV particles matain its fluctuations.Thus can infer that the SD structure and ESV structure magnetite particles can be used as a good paleomagnetic information carrier for paleomagnetism research.This method can broaden the size range of good magnetic-carrying particles to a certain extent,thereby improving the extraction of effective paleomagnetic information.