Hydrothermal synthesis of NiFe2O4, Ni0.6Zn0.4Fe2O4 and Ni0.6Zn0.4Fe2O4/SrFe2O4: nanostructure, magnetic and dielectric properties

Abstract

NiFe₂O₄ (NF), Ni_0.6Zn_0.4Fe₂O₄ (NZF) and Ni_0.6Zn_0.4Fe₂O₄/SrFe₂O₄ (NZF/SF) nanostructures were prepared by hydrothermal synthesis at 180°C/48 h. The synthesis of NF shows nanoparticles of average size 19 nm. However, NZF and NZF/SF show nanowires of average diameter ~23 and 6 nm, and length 325 and 160 nm, respectively. A growth mechanism for fabrication of nanostructure is given. The X-ray diffraction pattern confirms the polycrystalline structure of spinel phase of NF and NZF and orthorhombic phase of SF ferrite. The microstructural analysis is confirmed by transmission electron microscopy. The ferromagnetic behaviour of each ferrite sample is confirmed by M-H hysteresis. However, the M-H hysteresis of composite NZF/SF also shows spring like vibrations which indicate a strong coupling between hard and soft phases. The higher value of remanent magnetization is observed in NZF/SF which is possible by combining soft/hard ferrite phase. The effect of low dimensions of NZF/SF nanostructure is to control dielectric constant with low loss up to higher frequency of 120 MHz, has been observed.