Pressler Kimo, Snoeren Thom J, Walsh Kelly M, Gamelin Daniel R
Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.
Nano Lett. 2023 Feb 22;23(4):1320-1326. doi: 10.1021/acs.nanolett.2c04533. Epub 2023 Feb 1.
The two-dimensional (2D) van der Waals ferromagnet CrI has been doped with the magnetic optical impurity Yb to yield materials that display sharp multiline Yb photoluminescence (PL) controlled by the magnetism of CrI. Magneto-PL shows that Yb magnetization is pinned to the magnetization of CrI. An effective internal field of ∼10 T at Yb is estimated, attributed to strong in-plane Yb-Cr superexchange coupling. The anomalously low energy of Yb PL in CrI reflects relatively high Yb-I covalency, contributing to Yb-Cr superexchange coupling. The Yb PL energy and line width both reveal the effects of spontaneous zero-field CrI magnetic ordering 2D layers below , despite the absence of net magnetization in multilayer samples. These results illustrate the use of optical impurities as "designer defects" to introduce unique functionality to 2D magnets.
二维范德华铁磁体CrI已被磁性光学杂质Yb掺杂，从而产生了一些材料，这些材料显示出由CrI的磁性控制的尖锐多线Yb光致发光（PL）。磁光致发光表明Yb磁化被固定在CrI的磁化上。估计Yb处的有效内场约为10 T，这归因于强面内Yb-Cr超交换耦合。CrI中Yb PL异常低的能量反映了相对较高的Yb-I共价性，这有助于Yb-Cr超交换耦合。尽管多层样品中没有净磁化，但Yb PL能量和线宽都揭示了低于二维层的自发零场CrI磁有序的影响。这些结果说明了使用光学杂质作为“设计缺陷”为二维磁体引入独特功能。
