Over 50% reduction in the formation energy of Co-based Heusler alloy films by two-dimensional crystallisation
Over 50% reduction in the formation energy of Co-based Heusler alloy films by two-dimensional crystallisation
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DOI：
10.1063/1.4886769
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发表时间：
2014-07-21
影响因子：
4
通讯作者：
Hirohata, Atsufumi
中科院分区：
文献类型：
--
作者：
Sagar, James;Fleet, Luke R.;Hirohata, Atsufumi
通过与当前半导体技术兼容的低温退火工艺形成高磁矩薄膜的结晶，对于开发能够利用自旋自由度的下一代器件至关重要。利用原位像差校正的电子显微镜，我们报道了一个235℃的钴基三元Heusler合金薄膜的晶化过程，它的初始形核是由27个晶胞引发的。晶化优先发生在<；111>；晶向，通过二维(2D)逐层生长模式；导致了具有[110]表面法线和[111]平面的晶粒。与块状样品相比，这种生长过程降低了50%以上的结晶能，同时仍然导致了高度有序的颗粒的生长，预计会产生高度的自旋极化。我们的发现表明，2D逐层生长使结晶能最小化，从而可能将高度自旋极化的合金薄膜应用到当前的芯片和存储技术中。(C)2014 AIP出版有限责任公司。
Crystalline formation of high magnetic-moment thin films through low-temperature annealing processes compatible with current semiconductor technologies is crucial for the development of next generation devices, which can utilise the spin degree of freedom. Utilising in-situ aberration corrected electron microscopy, we report a 235 degrees C crystallisation process for a Co-based ternary Heusler-alloy film whose initial nucleation is initiated by as few as 27 unit cells. The crystallisation occurs preferentially in the < 111 > crystalline directions via a two-dimensional (2D) layer-by-layer growth mode; resulting in grains with [110] surface normal and [111] plane facets. This growth process was found to reduce the crystallisation energy by more than 50% when compared to bulk samples whilst still leading to the growth of highly ordered grains expected to give a high degree of spin-polarisation. Our findings suggest that the 2D layer-by-layer growth minimises the crystallisation energy allowing for the possible implementation of highly spin-polarised alloy films into current chip and memory technologies. (C) 2014 AIP Publishing LLC.