Robust ferroelectric properties of organic croconic acid films grown on spintronically relevant substrates
Robust ferroelectric properties of organic croconic acid films grown on spintronically relevant substrates
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DOI：
10.1039/d0ma00147c
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
S. Mohapatra;V. Da Costa;Garen Avedissian;J. Arabski;W. Weber;M. Bowen;S. Boukari
中科院分区：
文献类型：
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作者：
S. Mohapatra;V. Da Costa;Garen Avedissian;J. Arabski;W. Weber;M. Bowen;S. Boukari
在有机铁电材料克酮酸中发现了稳定的室温铁电性，其极化值与无机铁电材料中发现的极化值相当，并且是有机铁电材料中最高的，这开辟了实现基于有机铁电体的无数纳米电子和自旋电子器件的可能性。这种可能性需要充分了解的铁电性能的克酮酸生长在表面上，通常采用在设备制造。虽然已经对相对较大的克酮酸晶体进行了几次宏观研究，但对薄膜的研究仅处于早期阶段。我们在金和钴表面上生长了克酮酸薄膜，这是常用的自旋电子器件中的金属电极，并在室温下使用非原位压电力显微镜研究了薄膜的铁电响应。我们发现，在克酮酸领域的极化反转是敏感的基板表面。使用相同的实验协议，我们观察到一个单一的，主要是在平面内的电域的钴基板的强大的极化反转，而极化反转是很难观察到的金基板。我们将这种差异归因于底物对克酮酸分子网络的影响。我们的研究表明，为了实现器件，必须注意克酮酸将沉积在其上的基底。在钴表面上的偏振转换是稳健的这一事实可以用于制造利用钴-克酮酸界面的多功能器件。
The discovery of stable room temperature ferroelectricity in Croconic Acid, an organic ferroelectric material, with polarization values on par with those found in inorganic ferroelectric materials and highest among organic ferroelectric materials, has opened up possibilities to realize myriads of nano-electronic and spintronic devices based on organic ferroelectrics. Such possibilities require an adequate understanding of the ferroelectric properties of Croconic Acid grown on surfaces that are commonly employed in device fabrication. While several macroscopic studies on relatively larger crystals of Croconic Acid have been performed, studies on thin films are only in their early stages. We have grown thin films of Croconic Acid on gold and cobalt surfaces, which are commonly used in spintronic devices as metallic electrodes, and studied the ferroelectric response of the films using ex-situ Piezoresponse Force Microscopy at room temperature. We show that the polarization reversal in Croconic Acid domains is sensitive to the substrate surface. Using the same experimental protocol, we observe the robust polarization reversal of a single, mostly in-plane electrical domain for a cobalt substrate, whereas polarization reversal is hardly observed for a gold substrate. We attribute this difference to the influence of substrates on the Croconic Acid molecular networks. Our study suggests that to realize devices one has to take care about the substrate on which Croconic Acid will be deposited. The fact that polarization switching is robust on cobalt surface can be used to fabricate multifunctional devices that utilize the cobalt-Croconic Acid interface.