The tuning of quantum magnetization for organic/inorganic hybrid materials composed of Mn12-acetate and azobenzene casted into PMMA films on PVA films

In order to examine the effects of polymer matrix substituting crystalline solvents and photoisomerization of azobenzene in photo-modulation of AC susceptibility discovered recently, we have compared various quantum magnetic properties of new organic/inorganic hybrid materials composed of Mn(12)-acetate (a typical single-molecule magnet, [Mn(12)(CH(3)COO)(16)(H(2)O)(4)O(12)]center dot 2CH(3)COOH center dot 4H(2)O) containing or not containing azobenzene casted into polymethylmethacrylate ( PMMA) films on Polyvinylalchol (PVA) films. The M-H hysteresis loops below blocking temperature for both materials exhibited distinct differences of the dM/dH vs. H plots, which suggested azobenzene as well as crystalline solvents resulted in tuning of magnetic properties. Moreover, the AC susceptibility at 0.1-1000 Hz frequencies provided activation energy U(eff) = 87 K from Arrhenius law for both materials, albeit Cole-Cole plots indicated perturbation of quantum magnetization for both hybrid materials in polymer matrix. (C) 2008 Elsevier B.V. All rights reserved.