Exchange coupling and its chemical trend studied by high-frequency EPR on heterometallic [Ln2Ni] complexes.
We applied high-frequency electron paramagnetic resonance to trinuclear 4f-3d heterometallic complexes, [{Ln(hfac)3}2{Ni(dpk)2(py)2}] (Ln = Y, Gd, Tb, and Ho; hfac = hexafluoroacetylacetonate, dpk = di-2-pyridyl ketoximate, and py = pyridine), and determined the exchange parameter J(Ln-Ni) as well as nickel(II) zero-field splitting parameters. In contrast to the antiferromagnetic Dy analogue, ferromagnetic couplings were precisely characterized as J(Gd-Ni)/kB = +0.301(4) K, J(Tb-Ni)/kB = +0.216(12) K, and J(Ho-Ni)/kB = +0.110(3) K (defined as -J(Ln-Ni)∑J(Ln)(z)S(Ni)).
Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo , Meguro-ku, Tokyo 153-8902, Japan.
Atsushi
A
Okazawa
Takashi
T
Shimada
Norimichi
N
Kojima
Shunsuke
S
Yoshii
Hiroyuki
H
Nojiri
Takayuki
T
Ishida