Layered metal–organic frameworks are promising candidates for new two-dimensional magnets, as their synthetic programmability of these materials can provide a route to diverse structural and electronic properties. However, such framework materials typically lack the heavy elements that engender magnetocrystalline anisotropy in the monolayer ferromagnets reported to date. Alternative sources of magnetic anisotropy are therefore needed in these materials. Here, we report the synthesis of single crystals of the framework material (NMe4)2[Fe2L3] (H2L = 3,6-dichloro-2,5-dihydroxybenzoquinone) and evaluate the angular dependence of its magnetic properties. Oriented-crystal magnetization measurements reveal strong uniaxial anisotropy, where the easy axis is aligned with the crystallographic c axis. While the spin carriers of this structure are isotropic $$S = ^5/_2$$ FeIII metal centers and $$S = ^1/_2$$ organic linkers, the anisotropy energy of the framework material is comparable to that of reported 2D ferromagnets. Density functional theory calculations indicate that the observed magnetocrystalline anisotropy arises from ligand-to-metal charge transfer that enhances the magnetic anisotropy of the otherwise isotropic Fe centers, suggesting that metal–ligand covalency can be utilized as a general additive for the development of 2D magnets. These results in this study show the possibility for (NMe4)2[Fe2L3] to retain magnetic order down to the 2D monolayer limit. In addition, the combination of large magnetic anisotropy and semiconducting character in (NMe4)2[Fe2L3] highlights its potential as a new 2D magnetic semiconductor.
Wang, Yiran, et al. "Strong Magnetocrystalline Anisotropy Arising from Metal–Ligand Covalency in a Metal–Organic Candidate for 2D Magnetic Order." Chemistry of Materials, vol. 33, no. 22, Nov. 2021. https://doi.org/10.1021/acs.chemmater.1c02670
Wang, Yiran, Ziebel, Michael E., Sun, Lei, Gish, J. Tyler, Pearson, Tyler J., Lu, Xue-Zeng, Thorarinsdottir, Agnes E., Hersam, Mark C., Long, Jeffrey R., Freedman, Danna E., Rondinelli, James M., Puggioni, Danilo, & Harris, T. David (2021). Strong Magnetocrystalline Anisotropy Arising from Metal–Ligand Covalency in a Metal–Organic Candidate for 2D Magnetic Order. Chemistry of Materials, 33(22). https://doi.org/10.1021/acs.chemmater.1c02670
Wang, Yiran, Ziebel, Michael E., Sun, Lei, et al., "Strong Magnetocrystalline Anisotropy Arising from Metal–Ligand Covalency in a Metal–Organic Candidate for 2D Magnetic Order," Chemistry of Materials 33, no. 22 (2021), https://doi.org/10.1021/acs.chemmater.1c02670
@article{osti_1865140,
author = {Wang, Yiran and Ziebel, Michael E. and Sun, Lei and Gish, J. Tyler and Pearson, Tyler J. and Lu, Xue-Zeng and Thorarinsdottir, Agnes E. and Hersam, Mark C. and Long, Jeffrey R. and Freedman, Danna E. and others},
title = {Strong Magnetocrystalline Anisotropy Arising from Metal–Ligand Covalency in a Metal–Organic Candidate for 2D Magnetic Order},
annote = {Layered metal–organic frameworks are promising candidates for new two-dimensional magnets, as their synthetic programmability of these materials can provide a route to diverse structural and electronic properties. However, such framework materials typically lack the heavy elements that engender magnetocrystalline anisotropy in the monolayer ferromagnets reported to date. Alternative sources of magnetic anisotropy are therefore needed in these materials. Here, we report the synthesis of single crystals of the framework material (NMe4)2[Fe2L3] (H2L = 3,6-dichloro-2,5-dihydroxybenzoquinone) and evaluate the angular dependence of its magnetic properties. Oriented-crystal magnetization measurements reveal strong uniaxial anisotropy, where the easy axis is aligned with the crystallographic c axis. While the spin carriers of this structure are isotropic $S = ^5/_2$ FeIII metal centers and $S = ^1/_2$ organic linkers, the anisotropy energy of the framework material is comparable to that of reported 2D ferromagnets. Density functional theory calculations indicate that the observed magnetocrystalline anisotropy arises from ligand-to-metal charge transfer that enhances the magnetic anisotropy of the otherwise isotropic Fe centers, suggesting that metal–ligand covalency can be utilized as a general additive for the development of 2D magnets. These results in this study show the possibility for (NMe4)2[Fe2L3] to retain magnetic order down to the 2D monolayer limit. In addition, the combination of large magnetic anisotropy and semiconducting character in (NMe4)2[Fe2L3] highlights its potential as a new 2D magnetic semiconductor.},
doi = {10.1021/acs.chemmater.1c02670},
url = {https://www.osti.gov/biblio/1865140},
journal = {Chemistry of Materials},
issn = {ISSN 0897-4756},
number = {22},
volume = {33},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2021},
month = {11}}
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Northwestern Univ., Evanston, IL (United States); Univ. of California, Berkeley, CA (United States); University of California, Berkeley, CA (United States)
Sponsoring Organization:
Camille and Henry Dreyfus Foundation; Institute of Nanotechnology (IIN); National Science Foundation (NSF); State of Illinois; USDOE Office of Science (SC); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
Grant/Contract Number:
AC02-05CH11231; SC0019356
OSTI ID:
1865140
Alternate ID(s):
OSTI ID: 2342086 OSTI ID: 1905576 OSTI ID: 1961803
Journal Information:
Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 22 Vol. 33; ISSN 0897-4756
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, Vol. 225, Issue 1162, p. 362-375https://doi.org/10.1098/rspa.1954.0209
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 240, Issue 826https://doi.org/10.1098/rsta.1948.0007