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Coercive Fields Above 6 T in Two Cobalt(II)–Radical Chain Compounds
Author(s) -
Liu Xiaoqing,
Feng Xiaowen,
Meihaus Katie R.,
Meng Xixi,
Zhang Yuan,
Li Liang,
Liu JunLiang,
Pedersen Kasper S.,
Keller Lukas,
Shi Wei,
Zhang YiQuan,
Cheng Peng,
Long Jeffrey R.
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202002673
Subject(s) - magnet , lanthanide , coercivity , radical , cobalt , hysteresis , materials science , magnetization , molecular magnets , oxide , magnetic hysteresis , chain (unit) , crystallography , condensed matter physics , nanotechnology , magnetic field , chemistry , physics , organic chemistry , ion , metallurgy , quantum mechanics , astronomy
Lanthanide permanent magnets are widely used in applications ranging from nanotechnology to industrial engineering. However, limited access to the rare earths and rising costs associated with their extraction are spurring interest in the development of lanthanide‐free hard magnets. Zero‐ and one‐dimensional magnetic materials are intriguing alternatives due to their low densities, structural and chemical versatility, and the typically mild, bottom‐up nature of their synthesis. Here, we present two one‐dimensional cobalt(II) systems Co(hfac) 2 (R‐NapNIT) (R‐NapNIT=2‐(2′‐(R‐)naphthyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, R=MeO or EtO) supported by air‐stable nitronyl nitroxide radicals. These compounds are single‐chain magnets and exhibit wide, square magnetic hysteresis below 14 K, with giant coercive fields up to 65 or 102 kOe measured using static or pulsed high magnetic fields, respectively. Magnetic, spectroscopic, and computational studies suggest that the record coercivities derive not from three‐dimensional ordering but from the interaction of adjacent chains that compose alternating magnetic sublattices generated by crystallographic symmetry.