arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1406.5488cond-mat.mtrl-sci
收藏

钙钛矿超晶格室温线性磁电性的设计

Linear magnetoelectricity at room temperature in perovskite superlattices by design

Saurabh Ghosh, Hena Das, Craig J. Fennie

摘要:

发现在室温下显示线性磁电效应的材料是一个挑战。这种材料可以促进基于磁场电场控制的新型设备。在这里,我们提出了简单的、化学上直观的设计规则,以基于$Pnma$铁氧体钙钛矿的“双色”分层来识别一类新的体磁电材料,例如,LaFeO $_3$ / LnFeO $_3$超晶格,其中Ln =镧系元素阳离子。我们使用第一性原理密度泛函理论计算来证实这些想法。此外,我们阐明了这种效果的起源,并表明它是一个一般的后果,分层的任何双色,$Pnma$钙钛矿超晶格中的组成层的数量是奇数(导致一种形式的混合不适当的铁电性)和古迪纳夫- Kanamori规则。在这里,极性扭曲诱导弱铁磁性和线性磁电效应。我们的计算表明,该效应的大小是2-3倍,观察到的原型磁电材料,铬$_2$ O $_3$。我们使用一个简单的平均场模型表明,所考虑的材料在室温以上的磁性顺序。

英文摘要:

Discovering materials that display a linear magnetoelectric effect at room temperature is challenge. Such materials could facilitate novel devices based on the electric-field control of magnetism. Here we present simple, chemically intuitive design rules to identify a new class of bulk magnetoelectric materials based on the 'bicolor' layering of $Pnma$ ferrite perovskites, e.g., LaFeO$_3$/ LnFeO$_3$ superlattices for which Ln = lanthanide cation. We use first-principles density-functional theory calculations to confirm these ideas. Additionally, we elucidate the origin of this effect and show it is a general consequence of the layering of any bicolor, $Pnma$ perovskite superlattice in which the number of constituent layers are odd (leading to a form of hybrid improper ferroelectricity) and Goodenough- Kanamori rules. Here, the polar distortions induce both weak ferromagnetism and a linear magnetoelectric effect. Our calculations suggest that the effect is 2-3 times greater in magnitude than that observed for the prototypical magnetoelectric material, Cr$_2$O$_3$. We use a simple mean field model to show that the considered materials order magnetically above room temperature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑