Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching

Li, Guan-Qi; Zheng, Xiang-Yu; Wang, Jun-Lin; Lu, Xian-Yang; Wu, Jing; Cai, Jian-Wang; Meng, Hao; Liu, Bo; Ostler, Thomas A; Xu, Yong-Bing

Abstract

The heating and helicity effects induced by circularly polarized laser excitation are entangled in the helicity-dependent all-optical switching (HD-AOS), which hinders understanding the magnetization dynamics involved. Here, applying a dual-pump laser excitation, first with a linearly polarized (LP) laser pulse followed by a circularly polarized (CP) laser pulse, the timescales and contribution from heating and helicity effects in HD-AOS were identified with a Pt/Co/Pt triple-layer. When the LP laser pulses preheat the sample to a nearly fully demag-netized state, the CP laser pulses with a power reduced by 80% switch the sample's magnetization. By varying the time delay between the two pump pulses, the results show that the helicity effect, which gives rise to the deterministic helicity-induced switching, arises almost instantly within 200 fs close to the pulse width upon laser excitation. The results reveal that the transient magnetization state upon which CP laser pulses impinge is the key factor for achieving HD-AOS, and importantly, the tunability between heating and helicity effects with the unique dual-pump laser excitation approach will enable HD-AOS in a wide range of magnetic material systems having wide-ranging implications for potential ultrafast spintronics applications.

Citation

Li, G., Zheng, X., Wang, J., Lu, X., Wu, J., Cai, J., …Xu, Y. (2023). Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching. Rare Metals, 42(1), 234-243. https://doi.org/10.1007/s12598-022-02117-8

• Journal Article Type: Article
• Acceptance Date: Apr 15, 2022
• Online Publication Date: Oct 22, 2022
• Publication Date: 2023-01
• Deposit Date: Jan 16, 2023
• Publicly Available Date: Jan 17, 2023
• Journal: Rare Metals
• Print ISSN: 1001-0521
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 42
• Issue: 1
• Pages: 234-243
• DOI: https://doi.org/10.1007/s12598-022-02117-8
• Keywords: Helicity-dependent all-optical switching; Ultrafast laser; Ultrafast magnetization; Magneto-optical interaction
• Public URL: https://hull-repository.worktribe.com/output/4182903
• Publisher URL: https://link.springer.com/article/10.1007/s12598-022-02117-8