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

TY - JOUR

T1 - Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching

AU - Li, Guan Qi

AU - Zheng, Xiang Yu

AU - Wang, Jun Lin

AU - Lu, Xian Yang

AU - Wu, Jing

AU - Cai, Jian Wang

AU - Meng, Hao

AU - Liu, Bo

AU - Ostler, Thomas A.

AU - Xu, Yong Bing

N1 - Funding Information: This work is financially supported by the National Key Research and Development Program of China (No. 2016YFA0300803), the National Natural Science Foundation of China (Nos. 61427812 and 11774160), the Natural Science Foundation of Jiangsu Province of China (No. BK20192006). X. Lu acknowledges the support of National Key R&D Program of China (No. 2021YFB3601600) and the Natural Science Foundation of Jiangsu Province of China (No. BK20200307). T. A. Ostler gratefully acknowledges the support of the UK EPSRC (No. EP/T027916/1). This work was supported by the EPSRC TERASWITCH project (project ID EP/T027916/1) Publisher Copyright: © 2022, The Author(s).

PY - 2023/1/1

Y1 - 2023/1/1

N2 - 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 demagnetized 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. Graphical abstract: [Figure not available: see fulltext.].

AB - 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 demagnetized 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. Graphical abstract: [Figure not available: see fulltext.].

KW - Helicity-dependent all-optical switching

KW - Magneto-optical interaction

KW - Ultrafast laser

KW - Ultrafast magnetization

UR - http://www.scopus.com/inward/record.url?scp=85140452243&partnerID=8YFLogxK

U2 - 10.1007/s12598-022-02117-8

DO - 10.1007/s12598-022-02117-8

M3 - Article

AN - SCOPUS:85140452243

SN - 1001-0521

VL - 42

SP - 234

EP - 243

JO - Rare Metals

JF - Rare Metals

IS - 1

ER -