Extraordinary role of Ce–Ni elements on the electrical and magnetic properties of Sr–Ba M-type hexaferrites

The structural, electrical and magnetic behavior of Sr{sub 0.5}Ba{sub 0.5-x}Ce{sub x}Fe{sub 12-y}Ni{sub y}O{sub 19} (where x = 0.00-0.10; y = 0.00-1.00) hexaferrite nanomaterials are reported in this paper. The structural analysis indicates that the Ce-Ni doped Sr-Ba M-type hexaferrite samples synthesized by the co-precipitation method are stoichiometric, single magnetoplumbite phase with crystallite sizes in the range of 35-48 nm. The dc-electrical resistivity of the pure Sr-Ba hexaferrite is enhanced to almost 10{sup 2} times by doping with Ce-Ni contents of x = 0.06; y = 0.60. The dielectric constant and dielectric loss tangent decrease to values {approx}14 and 10{sup 5} Hz are observed for the samples with Ce content of x > 0.06. The values of saturation magnetization increase from 66.32 to 84.33 emu/g and remanance magnetization from 42.64 to 56.01 emu/g but coercivity decreases from 2.85 to 1.59 kOe by substitution of Ce-Ni. Sharp ferri-paramagnetic transition is observed in the samples, which is confirmed by DSC results. Ce-Ni substitution acts to reduce the electron-hopping between Fe{sup 2+}/Fe{sup 3+} ions and also improves the magnetic properties. These characteristics are desirable for their possible use inmore » microwave and chip devices.« less