| In this paper, the crystal structure and magnetic properties of Sr2Fe1-xMnxMoO6 ( 0 .1≤x≤0.9) have been investigated. The lattice constants and the cation ordering increase monotonousely with the Mn content. The dynamic magnetic properties of the series of compounds have been studied by ac susceptibility and dc magnetization, including relaxation and aging studies. We combine the results of magnetic, specific heat properties and transport measurement to construct the magnetic phase diagram of the family of double perovskite Sr2Fe1-xMnxMoO6. We have found ferromagnetic ordering for lightly and antiferromagnetic ordering for heavily Mn-substituted respectively, while intermediate substitution express to reentrant spin glass behavior. The reentrant spin glass behavior accompanied by the anomalous multiple magnetic transitions might be due to the competing interactions between the FM phase and antiferromagnetic interaction induced by the Mn ion.The resistivities of these samples obtained by the Quantum Design physical properties measurement system (PPMS-9T) all show semiconductor behavior and increase by several orders of magnitude as x increases over a percolation threshold of 0.4. The MR of all samples with x≤are much larger than that of pure SFMO under low field at 10 K, and a large MR with linear magnetic field dependence up to5 T was found for samples with x >0.4, and the maximum value of MR about 212 % was achieved for Mn=0.6. The origin of the MR is dominated by the direct inter-granular spin-dependent tunneling at low field and is consistent with the model of second-order tunneling process at high field.
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