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Magnetic‐Pole Flip by Millimeter Wave
Author(s) -
Ohkoshi Shinichi,
Yoshikiyo Marie,
Imoto Kenta,
Nakagawa Kosuke,
Namai Asuka,
Tokoro Hiroko,
Yahagi Yuji,
Takeuchi Kyohei,
Jia Fangda,
Miyashita Seiji,
Nakajima Makoto,
Qiu Hongsong,
Kato Kosaku,
Yamaoka Takehiro,
Shirata Masashi,
Naoi Kenji,
Yagishita Koichi,
Doshita Hiroaki
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202004897
Subject(s) - terahertz radiation , extremely high frequency , materials science , millimeter , spins , generator (circuit theory) , oxide , magnetic nanoparticles , nanoparticle , geomagnetic reversal , optoelectronics , nanotechnology , magnetic field , condensed matter physics , telecommunications , computer science , optics , physics , power (physics) , quantum mechanics , metallurgy
In the era of Big Data and the Internet of Things, data archiving is a key technology. From this viewpoint, magnetic recordings are drawing attention because they guarantee long‐term data storage. To archive an enormous amount of data, further increase of the recording density is necessary. Herein a new magnetic recording methodology, “focused‐millimeter‐wave‐assisted magnetic recording (F‐MIMR),” is proposed. To test this methodology, magnetic films based on epsilon iron oxide nanoparticles are prepared and a focused‐millimeter‐wave generator is constructed using terahertz (THz) light. Irradiating the focused millimeter wave to epsilon iron oxide instantly switches its magnetic pole direction. The spin dynamics of F‐MIMR are also calculated using the stochastic Landau–Lifshitz–Gilbert model considering all of the spins in an epsilon iron oxide nanoparticle. In F‐MIMR, the heat‐up effect of the recording media is expected to be suppressed. Thus, F‐MIMR can be applied to high‐density magnetic recordings.