论文标题
迈向合成铁磁铁的高全光数据编写率
Towards high all-optical data writing rates in synthetic ferrimagnets
论文作者
论文摘要
尽管使用FS激光脉冲的全光磁化切换已经获得了很大的技术兴趣，但几乎没有研究最终的数据速率。最近已经显示，在GDCO合金中发生切换事件后，第二次到达7 ps的激光脉冲可以始终如一地切换磁化。但是，尚不清楚在分层的铁磁系统中是否相同，这对应用具有很大的希望。在这项工作中，我们研究了使用两个FS激光脉冲的合成铁磁CO/GD双层中的两个随后的切换事件之间的最小时间延迟。我们通过实验表明，一致开关所需的最小时间延迟可能低至10 ps。此外，我们证明了工程热扩散远离磁性材料的重要性，并控制了激光脉冲功率。这种行为是使用建模再现的，即使磁化未完全回收，我们发现第二个开关也可以发生。我们进一步证实，热扩散是减少第二个开关的时间延迟的关键因素，同时也确认了对激光功率的临界依赖性。
Although all-optical magnetization switching with fs laser pulses has garnered much technological interest, the ultimate data rates achievable have scarcely been investigated. Recently it has been shown that after a switching event in a GdCo alloy, a second laser pulse arriving 7 ps later can consistently switch the magnetization. However, it is as of yet unknown whether the same holds in layered ferrimagnetic systems, which hold much promise for applications. In this work we investigate the minimum time delay required between two subsequent switching events in synthetic ferrimagnetic Co/Gd bilayers using two fs laser pulses. We experimentally demonstrate that the minimum time delay needed for consistent switching can be as low as 10 ps. Moreover, we demonstrate the importance of engineering heat diffusion away from the magnetic material, as well as control over the laser pulse power. This behavior is reproduced using modelling, where we find that the second switch can occur even when the magnetization is not fully recovered. We further confirm that heat diffusion is a critical factor in reducing the time delay for the second switch, while also confirming a critical dependence on laser power.
