A multiferroic material [NH2-CH+-NH2]Co(HCOO)3 of metal-organic frameworks with weak ferromagnetism and dielectric relaxation

In order to seek for the single-phase multiferroic metal-organic frameworks (MOFs) materials, we prepared a multiferroic material [NH2-CH+-NH2]Co(HCOO)3 (FMDCo) by solvothermal method. We found that it had weak ferromagnetism below 12.5 K with the coercive fields (Hc) of 560 Oe, remnant magnetization (Mr) of 7.67 emu/g and saturation magnetization (Ms) of 10.3 emu/g and exhibited obvious dielectric relaxation. The octahedral metal ions (Co2+) were linked by formate (HCOO-) ligands. The AmineH+ cation (NH2-CH+-NH2) were located within the cube-like cavities of the framework and formed extensive hydrogen bonds with the framework. This improved the phase transition temperature and thermal stability. This finding helps to understand the nature of magnetic and electric ordering in the MOFs.