Single-molecule magnet behavior enhanced by magnetic coupling between 4f and 3d spins

We synthesized and characterized a new compound [{Dy(hfac)(3)}(2)Pd(dpk)(2)] ([Dy(2)Pd]; Hdpk = di-2-pyridyl ketoxime), which is isostructural with the known [Dy(2)Cu] and [Dy(2)Ni]. The study of the [Dy(2)Pd] compound containing diamagnetic Pd ion is indispensable to clarify a contribution of the exchange coupling for a 4f-3d single-molecule magnet behavior. From the ac susceptibility measurements on [Dy(2)Pd], we obtained Delta/k(B) = 28.6(11) K and T(B) = 1.1 K. In accordance with the blocking behavior, the pulsed-field magnetization showed the hysteresis behavior below 1.1 K. These parameters on [Dy(2)Pd] having S(Pd) = 0 was compared with those of the derivatives having S(Cu) = 1/2 (Delta/k(B) = 47 K and T(B) = 1.8 K) and S(Ni) = 1 (Delta/k(B) = 62(4) K and T(B) = 2.5 K). The T(B) and Delta steadily increase with the increasing 3d(4d) spin quantum number. (C) 2011 Elsevier Ltd. All rights reserved.