A perspective on ultrafast magnetization switching in ferromagnets using helicity-independent optical pulses

• Published in: Journal of physics. D, Applied physics Vol. 58; no. 10; pp. 102001 - 102021
• Main Authors: Polley, Debanjan, Bokor, Jeffrey
• Format: Journal Article
• Language: English
• Published: IOP Publishing 10.03.2025
• Subjects: ferromagnets; opto-spintronics; perspective; ultrafast magnetization switching
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/1361-6463/ada1e0

We offer a brief overview of the present status of ultrafast helicity-independent all-optical magnetization switching (HI-AOS) phenomena in ferromagnet (FM) films and multilayers. The discovery of HI-AOS in ferrimagnet alloys dates back to 2011. From an application standpoint, utilizing HI-AOS in an FM brings about several benefits. One of these advantages is its enhanced spin polarization, which leads to a higher tunneling magneto-resistance (TMR) across a magnetic tunnel junction device. The enhanced TMR greatly enhances its reading capability. Time-resolved and single-shot magneto-optical Kerr effect measurement has successfully enabled the detection of magnetization switching. The magnetization reversal speed stays within the range of tens of picoseconds. There are two methods to achieve HI-AOS in an FM: (1) ultrafast spin-current-induced magnetization switching, and (2) ultrafast exchange interaction-dominated magnetization switching. We conduct a comprehensive analysis of a selection of recent academic publications that delve into both of these subjects and offer a succinct assessment of the present status of the ultrafast HI-AOS phenomenon in FMs. Finally, we discuss the latest developments in tackling the obstacles the HI-AOS mechanism faces and the exciting prospects for developing a high-speed spintronic memory device.