2025-05-23 東京科学大学
図1. ダイヤモンド量子センサを用いた交流磁気特性の可視化。Drive coilが発生する交流磁界が軟磁性CoFeB-SiO2薄膜を駆動。NVセンタにより交流磁気特性が可視化。
＜関連情報＞
- https://www.isct.ac.jp/ja/news/5qjf86r95gyx
- https://www.isct.ac.jp/plugins/cms/component_download_file.php?type=2&pageId=&contentsId=1&contentsDataId=1571&prevId=&key=eb6ca8dace4ebb154dde5fe66ec07f1e.pdf&fileName=sciencetokyopr20250523-hatano
- https://www.nature.com/articles/s43246-025-00812-4
ダイヤモンド量子センサーを用いた軟磁性薄膜の交流磁化応答のイメージング Imaging AC magnetization response of soft magnetic thin films using diamond quantum sensors
Ryota Kitagawa,Aoi Nakatsuka,Teruo Kohashi,Takeyuki Tsuji,Honami Nitta,Kosuke Mizuno,Yota Takamura,Shigeki Nakagawa,Takayuki Iwasaki,Amir Yacoby & Mutsuko Hatano
Communications Materials Published:23 May 2025
DOI:https://doi.org/10.1038/s43246-025-00812-4
Abstract
The energy loss in inductor core is a significant limitation in high-frequency power electronics. For evaluating and optimizing soft magnets, simultaneous imaging of both amplitude and phase of AC stray fields beyond 10 kHz is crucial. Here, we develop an imaging technique for analyzing AC magnetization response using diamond quantum sensors. For frequencies up to 200 kHz, we propose a measurement protocol, Qubit Frequency Track (Qurack), where microwave frequency modulation tracks qubit frequency oscillations. For higher frequencies above MHz, quantum heterodyne (Qdyne) imaging is employed. The soft magnetic CoFeB–SiO2 thin films, developed for high-frequency inductors, exhibit near-zero phase delay up to 2.3 MHz, indicating negligible energy loss. Moreover, the energy loss depends on the anisotropy: when the magnetization is driven along the easy axis, phase delay increases with frequency, signifying higher energy dissipation. These results suggest potential applications in analyzing soft magnets and improving the performance of power electronics.
