Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching
Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching
复制标题
DOI：
10.1007/s12598-022-02117-8
复制
发表时间：
2020-09
期刊：
影响因子：
8.8
通讯作者：
Guanqiao Li;Xiangyu Zheng;Junlin Wang;Xianyang Lu;Jing Wu;J. Cai;Hao Meng;Bo Liu;T. Ostler;Yongbing Xu
中科院分区：
文献类型：
--
作者：
Guanqiao Li;Xiangyu Zheng;Junlin Wang;Xianyang Lu;Jing Wu;J. Cai;Hao Meng;Bo Liu;T. Ostler;Yongbing Xu
圆偏振激光激发产生的热效应和螺旋度效应在依赖螺旋度的全光开关(HD-AOS)中纠缠在一起，这阻碍了人们对其中的磁化动力学的理解。在双泵浦光激励下，首先采用线偏振(LP)激光脉冲，然后是圆偏振(CP)激光脉冲，用铂/钴/铂三层膜确定了HD-AOS中加热和螺旋度效应的时间尺度和贡献。当LP激光脉冲将样品预热到几乎完全退磁状态时，功率降低80%的CP激光脉冲切换样品的磁化。通过改变两个泵浦脉冲之间的时间延迟，结果表明，在激光激发时，螺旋度效应在接近脉冲宽度的200fs范围内几乎是瞬间发生的，这种螺旋度效应导致了确定性的螺旋度诱导开关。结果表明，CP激光脉冲入射的瞬时磁化状态是实现HD-AOS的关键因素，重要的是，利用独特的双泵浦光激发方法，在加热效应和螺旋度效应之间的可调谐将使HD-AOS能够在广泛的磁性材料系统中应用，对潜在的超快自旋电子学应用具有广泛的意义
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