论文标题
具有巨大极化和巨大磁矩
Multiferroic nitride perovskites with giant polarizations and large magnetic moments
论文作者
论文摘要
数十年来，已经追求了铁电和磁性之间的耦合的多表情。但是，由于铁电和磁性之间的共同权衡，它们的磁性性能仍然受到限制。在这里，提出了一个氮化物钙钛矿家族，作为具有突出物理特性和非平凡机制的多表情。将GDWN $ _3 $作为原型，我们的第一原理计算发现，其钙钛矿阶段具有较大的极性（例如$ 111.3 $ $ $ $ $ $ $ $ $ $ c/cm $^2 $ $ r3c $相位）和一个磁性时刻$ 7 $ $ $ $ $ $ $ $ _ {\ rm b} $ _ {\ rm b} $/gd $/更有趣的是，其铁电源是多重的，gd $^{3+} $和W $^{6+} $ ions的贡献与其姊妹成员Lawn $ _3 $不同，在该$ _3 $中几乎来自W $^$^{6+} $ ions。随着稀土离子大小的减小，A位置离子将越来越有助于铁电不稳定。考虑到小稀土离子可以是氮化物钙钛矿中适当的铁电性和磁性的主要起源，我们的工作为使用非常规机制和最佳性能追求更多多效应提供了途径。
Multiferroics with coupling between ferroelectricity and magnetism have been pursued for decades. However, their magnetoelectric performances remain limited due to the common trade-off between ferroelectricity and magnetism. Here, a family of nitride perovskites is proposed as multiferroics with prominent physical properties and nontrivial mechanisms. Taking GdWN$_3$ as a prototype, our first-principles calculations found that its perovskite phases own large polarizations (e.g. $111.3$ $μ$C/cm$^2$ for the $R3c$ phase) and a magnetic moment $7$ $μ_{\rm B}$/Gd$^{3+}$. More interestingly, its ferroelectric origin is multiple, with significant contributions from both Gd$^{3+}$ and W$^{6+}$ ions, different from its sister member LaWN$_3$ in which the ferroelectricity almost arises from W$^{6+}$ ions only. With decreasing size of rare earth ions, the A site ions would contribute more and more to the ferroelectric instability. Considering that small rare earth ions can be primary origins of both proper ferroelectricity and magnetism in nitride perovskites, our work provides a route to pursuit more multiferroics with unconventional mechanisms and optimal performances.
