Effect of Eu–Ni substitution on electrical and dielectric properties of Co–Sr–Y-type hexagonal ferrite

• Single phase nanostructured Sr2Co2−xNix EuyFe12−yO22 were synthesized by the microemulsion method.
• The materials show semiconducting behavior.
• The high resistivity makes these materials useful for high frequency applications.
• The Curie temperature decreases with the substituents.

Single phase nanostructured Eu–Ni substituted Y-type hexaferrites with nominal composition Sr2Co2−xNix EuyFe12−yO22 (x = 0.0–1, y = 0.0–0.1) were synthesized by the normal microemulsion method. X-ray diffraction (XRD) technique was employed for phase analysis and indexing of each pattern corroborates that well defined Y-type crystalline phase is formed. It is observed that DC resistivity enhanced which is accredited to room temperature resistivity differences of dopant and host ions. The hopping of electrons and jumping of holes are responsible for conduction below Curie temperature (TC), whereas above Curie temperature is due to polaron hopping. The decrease in TC may be due to the fact that Eu–Fe interactions on the B sites are weaker than Fe–Fe interaction. The dispersion in the dielectric constant ɛ′(f) favor the occurrence of peaks in the tan δ(f). The extraordinary values of resistivity and small dielectric loss make these materials pre-eminent contestant for high frequency applications.

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