TY - JOUR
T1 - Exchange couplings in one-dimensionally arrayed 4f-3d heterometallic [Ln2Cu2]n compounds
T2 - A chemical trend of the coupling parameter
AU - Okazawa, Atsushi
AU - Fujiwara, Kei
AU - Watanabe, Ryo
AU - Kojima, Norimichi
AU - Yoshii, Shunsuke
AU - Nojiri, Hiroyuki
AU - Ishida, Takayuki
N1 - Funding Information:
This work was partly supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Nos. 21110513 and 22350059 ) and the Inter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University. A part of this work was performed at CINTS, Tohoku University. H.N. has been supported by GCOE program: Materials Integration, Tohoku University, Japan.
PY - 2011/11/28
Y1 - 2011/11/28
N2 - Heterometallic polymeric coordination compounds [{Ln(hfac) 2(CH3OH)}2{Cu(dmg)(Hdmg)}2] n (abbreviated as [Ln2Cu2]n) involving light lanthanoid ions, Pr, Nd, Sm, and Eu, were synthesized, where H2dmg and Hhfac stand for dimethylglyoxime and 1,1,1,5,5,5- hexafluoropentane-2,4-dione, respectively. The X-ray crystallographic analysis shows that their structures are isomorphous to those of the known heavy lanthanoid analogs. The exchange couplings were evaluated by high-frequency electron paramagnetic resonance and pulsed-field magnetization studies, giving ferromagnetic exchange parameters: JPr-Cu/kB = 0.039(1) K, JNd-Cu/kB = 0.38(1) K, JSm-Cu/kB = 0.95(2) K, and no interaction between Eu and Cu ions. A significant trend is found in the order of the periodic table. The ferro- and antiferromagnetic 4f-3d couplings were characterized for the light and heavy lanthanoid derivatives, respectively. The magnitude of JLn-Cu decreases with a decrease of the 4f-spin portion, i.e., the number of unpaired electrons, whether the coupling is ferro- or antiferromagnetic.
AB - Heterometallic polymeric coordination compounds [{Ln(hfac) 2(CH3OH)}2{Cu(dmg)(Hdmg)}2] n (abbreviated as [Ln2Cu2]n) involving light lanthanoid ions, Pr, Nd, Sm, and Eu, were synthesized, where H2dmg and Hhfac stand for dimethylglyoxime and 1,1,1,5,5,5- hexafluoropentane-2,4-dione, respectively. The X-ray crystallographic analysis shows that their structures are isomorphous to those of the known heavy lanthanoid analogs. The exchange couplings were evaluated by high-frequency electron paramagnetic resonance and pulsed-field magnetization studies, giving ferromagnetic exchange parameters: JPr-Cu/kB = 0.039(1) K, JNd-Cu/kB = 0.38(1) K, JSm-Cu/kB = 0.95(2) K, and no interaction between Eu and Cu ions. A significant trend is found in the order of the periodic table. The ferro- and antiferromagnetic 4f-3d couplings were characterized for the light and heavy lanthanoid derivatives, respectively. The magnitude of JLn-Cu decreases with a decrease of the 4f-spin portion, i.e., the number of unpaired electrons, whether the coupling is ferro- or antiferromagnetic.
KW - EPR
KW - ESR
KW - Exchange interaction
KW - Lanthanide
KW - Lanthanoid
KW - Rare earth metal
KW - Single-molecule magnet
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U2 - 10.1016/j.poly.2011.03.007
DO - 10.1016/j.poly.2011.03.007
M3 - Article
AN - SCOPUS:82255175260
SN - 0277-5387
VL - 30
SP - 3121
EP - 3126
JO - Polyhedron
JF - Polyhedron
IS - 18
ER -