Abstract
We present the synthesis and characterization of a fatty acid ligated Mniz, [Mn12O12(CH3(CH2)(16)CO2)(11)(CH3CO2)(5)(H2O)(4)], Mn-12-Stearate (2), a molecular nanomagnet of Mn-12 family that exhibits the enhanced solubility (in organic solvents) and aqueous stability. The chemical composition and morphology of Mn-12-Stearate have been established using FF-IR, UV-Vis, Raman and H-1 NMR spectroscopy, XRD, elemental analysis, TGA and electron microscopic techniques. The powder XRD and HR-TEM of compound 2 have revealed the formation of crystalline structure. The FC and ZFC magnetization (M) as a function of temperature (T) shows a blocking temperature T-B similar to 3.0 K. At T <= 3 K, the presence of hysteresis and periodic steps in the measured M-H loops indicate the presence of quantum tunnelling of magnetization (QTM). In the same T region, the observed decrease of magnetic relaxation rate with a decrease in T further implies the QTM to be thermally assisted. The estimated anisotropy energy barrier is found to be similar to 35 K. (C) 2016 Elsevier B.V. All rights reserved.