小行星龙宫纳米级磁畴状态的可视化

Visualization of nanoscale magnetic domain states in the asteroid Ryugu.

作者信息

Kimura Yuki, Kato Takeharu, Tanigaki Toshiaki, Akashi Tetsuya, Kasai Hiroto, Anada Satoshi, Yoshida Ryuji, Yamamoto Kazuo, Nakamura Tomoki, Sato Masahiko, Amano Kana, Kikuiri Mizuha, Morita Tomoyo, Kagawa Eiichi, Yada Toru, Nishimura Masahiro, Nakato Aiko, Miyazaki Akiko, Yogata Kasumi, Abe Masanao, Okada Tatsuaki, Usui Tomohiro, Yoshikawa Makoto, Saiki Takanao, Tanaka Satoshi, Terui Fuyuto, Nakazawa Satoru, Yurimoto Hisayoshi, Noguchi Takaaki, Okazaki Ryuji, Yabuta Hikaru, Naraoka Hiroshi, Sakamoto Kanako, Watanabe Sei-Ichiro, Tsuda Yuichi, Tachibana Shogo

机构信息

Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.

Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan.

出版信息

Sci Rep. 2023 Aug 29;13(1):14096. doi: 10.1038/s41598-023-41242-x.

DOI:10.1038/s41598-023-41242-x

PMID:37644091

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10465612/

Abstract

In the samples collected from the asteroid Ryugu, magnetite displays natural remanent magnetization due to nebular magnetic field, whereas contemporaneously grown iron sulfide does not display stable remanent magnetization. To clarify this counterintuitive feature, we observed their nanoscale magnetic domain structures using electron holography and found that framboidal magnetites have an external magnetic field of 300 A m, similar to the bulk value, and its magnetic stability was enhanced by interactions with neighboring magnetites, permitting a disk magnetic field to be recorded. Micrometer-sized pyrrhotite showed a multidomain magnetic structure that was unable to retain natural remanent magnetization over a long time due to short relaxation time of magnetic-domain-wall movement, whereas submicron-sized sulfides formed a nonmagnetic phase. These results show that both magnetite and sulfide could have formed simultaneously during the aqueous alteration in the parent body of the asteroid Ryugu.

摘要

在从小行星龙宫采集的样本中，磁铁矿由于星云磁场而呈现天然剩余磁化，而同期生长的硫化铁则不显示稳定的剩余磁化。为了阐明这一违反直觉的特征，我们使用电子全息术观察了它们的纳米级磁畴结构，发现莓球状磁铁矿具有300 A/m的外部磁场，与体值相似，并且其磁稳定性通过与相邻磁铁矿的相互作用而增强，从而能够记录盘状磁场。微米级的磁黄铁矿显示出多畴磁结构，由于磁畴壁运动的弛豫时间短，无法长时间保留天然剩余磁化，而亚微米级的硫化物形成了非磁性相。这些结果表明，磁铁矿和硫化物可能在小行星龙宫母体的水蚀变过程中同时形成。