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Photoinduced Magnetization with a High Curie Temperature and a Large Coercive Field in a Co‐W Bimetallic Assembly
Author(s) -
Ozaki Noriaki,
Tokoro Hiroko,
Hamada Yoshiho,
Namai Asuka,
Matsuda Tomoyuki,
Kaneko Souhei,
Ohkoshi Shinichi
Publication year - 2012
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201102727
Subject(s) - materials science , curie temperature , magnetization , ferromagnetism , coercivity , phase transition , condensed matter physics , phase (matter) , valence (chemistry) , curie , nuclear magnetic resonance , magnetic field , chemistry , physics , organic chemistry , quantum mechanics
The crystal structure, magnetic properties, and temperature‐ and photoinduced phase transition of [{Co II (4‐methylpyridine)(pyrimidine)} 2 {Co II (H 2 O) 2 }{W V (CN) 8 } 2 ]·4H 2 O are described. In this compound, a temperature‐induced phase transition from the Co II ( S = 3/2)‐NC‐W V ( S = 1/2) [high‐temperature (HT)] phase to the Co III ( S = 0)‐NC‐W IV ( S = 0) [low temperature (LT)] phase is observed due to a charge‐transfer‐induced spin transition. When the LT phase is irradiated with 785 nm light, ferromagnetism with a high Curie temperature ( T C ) of 48 K and a gigantic magnetic coercive field ( H c ) of 27 000 Oe are observed. These T C and H c values are the highest in photoinduced magnetization systems. The LT phase is optically converted to the photoinduced phase, which has a similar valence state as the HT phase due to the optically induced charge‐transfer‐induced spin transition.