Dual-shot dynamics and ultimate frequency of all-optical magnetic recording on GdFeCo

Sicong Wang; Chen Wei; Yuanhua Feng; Hongkun Cao; Wenzhe Li; Yaoyu Cao; Bai-Ou Guan; Arata Tsukamoto; Andrei Kirilyuk; Alexey V Kimel; Xiangping Li

doi:10.1038/s41377-020-00451-z

Dual-shot dynamics and ultimate frequency of all-optical magnetic recording on GdFeCo

Light Sci Appl. 2021 Jan 6;10(1):8. doi: 10.1038/s41377-020-00451-z.

Authors

Sicong Wang^{1

2}, Chen Wei¹, Yuanhua Feng³, Hongkun Cao¹, Wenzhe Li⁴, Yaoyu Cao¹, Bai-Ou Guan¹, Arata Tsukamoto⁵, Andrei Kirilyuk^{2

6}, Alexey V Kimel⁷, Xiangping Li⁸

Affiliations

¹ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.
² Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
³ Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou, 510632, China.
⁴ Institute of New Energy Technology, Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou, 510632, China.
⁵ College of Science and Technology, Nihon University, 7-24-1 Funabashi, Chiba, 274-8501, Japan.
⁶ FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands.
⁷ Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands. Aleksei.Kimel@ru.nl.
⁸ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China. xiangpingli@jnu.edu.cn.

Abstract

Although photonics presents the fastest and most energy-efficient method of data transfer, magnetism still offers the cheapest and most natural way to store data. The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing. The discovery of all-optical magnetization reversal in GdFeCo with the help of 100 fs laser pulses has further aroused intense interest in this compelling problem. Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching, the latter remains virtually unknown. Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd₂₇Fe_63.87Co_9.13. Varying the intensities of the shots and the shot-to-shot separation, we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits. It is shown that although magnetic writing launched by the first shot is completed after 100 ps, a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps. Using two shots partially overlapping in space and minimally separated by 300 ps, we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.