Tuning the structural and magnetic properties of MnZn nano-ferrites synthesized under a high magnetic field

Abstract A route for improving the saturation magnetization (MS) and lowering magnetic loss of nanocrystalline MnZn ferrites has been reported. Mn0.6Zn0.4Fe2O4 nano-particles were synthesized by phase transformation method under dc magnetic field of 0, 2, 4, and 6 T, respectively. The magnetic field enhances the lattice strain. The Ms of the sample prepared at 6 T is ∼18% and ∼16% higher than that of the sample prepared at 0 T at 120 K and 300 K, respectively. The MS at 120 K increases with the fabrication field up to 6 T. The blocking temperatures are ∼65 K and ∼40 K for the samples prepared at 0 T and 6 T, respectively. Results of a.c. magnetic properties show that the 6 T sample has a smaller imaginary susceptibility than the 0 T sample and the MnZn nano-ferrite system is a spin-glass one. The effects of magnetic field on the structure and magnetic properties of MnZn nano-ferrites are also discussed. The a.c. magnetic susceptibility experiments show dependency of the magnetic responses with applied frequency, revealing strongly magnetic interactions between the nano-sized particles.