Structural, spectral, electrical, dielectric and magnetic properties of Yb doped SrNiCo-X hexagonal nano-structured ferrites

Ytterbium (Yb) doped X-type hexagonal nano-sized ferrites (Sr2NiCoFe28O46) were fabricated by micro-emulsion method. The development of hexagonal structure of ferrite materials was confirmed by XRD analysis. The size of crystallites as determined by Scherrer's formula was found in the range 29–41 nm. The lattice strain of these ferrites was increased from 3.62 × 10−2 to 3.73 × 10−2 with the increased Yb-contents. The tetrahedral absorption bands shifted slightly towards higher frequency whereas octahedral bands shifted towards lower frequency side. The incorporation of Yb enhanced dc electrical resistivity significantly from 2.05 × 108 to 3.35 × 109 Ω-cm. The AC conductivity was increased with frequency whereas it decreased with the inclusion of Yb3+ ions. This distinctive behavior of these hexagonal ferrites may be suitable for microwave devices and electromagnetic attenuation applications. The doping of Yb3+ optimized coercivity whereas remanence and saturation magnetization were decreased. These ferrite materials can be used in longitudinal recording media due to more thermally stable and higher coercivity (577–671 Oe).