Structure and magnetic properties of a new single-molecule magnet Mn₁₁Fe₁O₁₂ (CH₃COO)₁₆(H₂O)₄\cdot2CH₃COOH\cdot4H₂O

A new single-molecule magnet Mn₁₁Fe₁O₁₂ (CH₃COO)₁₆(H₂O)₄?2CH₃COOH?4H₂O (Mn₁₁Fe₁) has been synthesized.The structure has been studied by the single crystal x-ray diffraction. The difference of Jahn--Teller distortion between Fe³⁺ and Mn³⁺ ion reveals that Fe³⁺ ion substitutes for Mn³⁺ ion on the Mn(3) sites in the Mn₁₂ skeleton. The temperature dependence of the magnetization gives a blocking temperature T_B=1.9K for Mn₁₁Fe₁. Based on the magnetization process analysis of the crystal at T=2K, we suggest that Mn₁₁Fe₁ has the ground state with a total spin S= 11/2.