Magnetic transitions in metal-organic frameworks of [(CH3)2NH2] FeII(HCOO)3, [(CH3)2NH2]CoII(HCOO)3 and [(CH3)2NH2]FeIII FeII(HCOO)6

In this work, we report the magnetic properties of metal-organic frameworks (MOF) of perovskite-like [(CH3)(2)NH2]M(HCOO)(3)(M = Fe-II, Co-II) and niccolite-like [(CH3)(2)NH2](FeFeII)-Fe-III(HCOO)(6) synthesized by a solvothermal route. The [(CH3)(2) NH2]Fe-II(HCOO)(3) exhibits two magnetic transitions at the temperatures of similar to 19 K for the canted weak ferromagnetic ordering and of similar to 10 K for the blocking of single-ion quantum magnet due to phase separation, while the [(CH3)(2)NH2]Co-II(HCOO)(3) shows one magnetic transition at the Curie temperature (T-C) of 14.9 K for the canted weak ferromagnetic ordering. Below the T-C values, spin-flop transition is observed in the magnetization curves of the [(CH3)(2)NH2]M(HCOO)(3) crystals with the critical magnetic field of about 104 kOe and 90 kOe at 10 K, respectively. Multistep-like jumping magnetization transitions induced by high magnetic field are observed in the ([CH3)(2)NH2](FeFeII)-Fe-III(HCOO)(6) in a temperature range between 10 and 25 K, indicating a complex spin configuration different from that in the [(CH3)(2)NH2]M(HCOO)(3) MOFs.