Magnetic‐Pole Flip by Millimeter Wave. Issue 48 (8th October 2020)

• Record Type: Journal Article
• Authors: Ohkoshi, Shin‐ichi; 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
• Is Part Of: Advanced materials. Volume 32:Issue 48(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-08
• Subjects: epsilon iron oxide -- magnetic recording -- magnetization reversal -- millimeter waves -- nanoparticles; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202004897
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: 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. Abstract : A new magnetic recording methodology, "focused‐millimeter‐wave‐assisted magnetic recording (F‐MIMR)", is demonstrated by irradiating a focused millimeter wave onto epsilon iron oxide. In F‐MIMR, the magnetic pole direction is instantly switched by the focused millimeter wave generated from terahertz light, and the heat‐up effect of the recording media is suppressed. Thus, F‐MIMR can be applied to high‐density magnetic recordings.