Multiple Magnetic Pole Reversals and Mössbauer Studies in Molecular-based Mixed Valency Ferrimagnet {[N(n-C4H9)4][MIIFeIII(C2O4)3]}n (M=Zn, Fe)

The Molecule magnets Materials {[N(n-C4H9)4][MIIFeIII(C2O4)3]}n (M=Zn Fe) were investigated by magnetic measurements and Mössbauer spectroscopy .In the complex {[N(n-C4H9)4][ZnII0.03FeII0.97 FeIII(C2O4)3]}n detailed investigation of the ferromagnetism behaviour, and a compensation temperature has found with the field being less than 1KOe. And the 57Fe Mössbauer measurements had been carried out in {[N(n-C4H9)4][FeIIFeIII(C2O4)3]}n to investigate the mixed valency character and antiferromagnetic coupling. Some ferrimagnets consisting of magnetic anisotropy ions and two or more types of antiferromagnetically ordered magnetic ions exhibit this behavior. As the temperature was lowered to 40 K, the FeIII doublet subspectrum almost completely turns into a sextet subspectrum. The hyperfine magnetic field increases as the temperature decreasing.