Magnetic Amplification at Yb3+ “Designer Defects” in the van der Waals Ferromagnet CrI3

The two-dimensional (2D) van der Waals ferromagnet CrI3 has been doped with the magnetic optical impurity Yb3+ to yield materials that display sharp multiline Yb3+ photoluminescence (PL) controlled by the magnetism of CrI3. Magneto-PL shows that Yb3+ magnetization is pinned to the magnetization of C...

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Bibliographic Details
Published in:Nano letters 2023-02, Vol.23 (4), p.1320-1326
Main Authors: Pressler, Kimo, Snoeren, Thom J., Walsh, Kelly M., Gamelin, Daniel R.
Format: Article
Language:English
Online Access:Get full text
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Summary:The two-dimensional (2D) van der Waals ferromagnet CrI3 has been doped with the magnetic optical impurity Yb3+ to yield materials that display sharp multiline Yb3+ photoluminescence (PL) controlled by the magnetism of CrI3. Magneto-PL shows that Yb3+ magnetization is pinned to the magnetization of CrI3. An effective internal field of ∼10 T at Yb3+ is estimated, attributed to strong in-plane Yb3+–Cr3+ superexchange coupling. The anomalously low energy of Yb3+ PL in CrI3 reflects relatively high Yb3+–I– covalency, contributing to Yb3+–Cr3+ superexchange coupling. The Yb3+ PL energy and line width both reveal the effects of spontaneous zero-field CrI3 magnetic ordering within 2D layers below T C, 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.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.2c04533