Comparative study of electrical and dielectric properties of Ho/Y ions modified Ba-Co-Sr Z-type nanohexaferrites

Two different compositions of Ho³⁺ and Y³⁺ doped Ba-Sr Z-type hexaferrite having composition, Ba_1.5Sr_1.5Co_2-zHo_zMn_xNi_yFe_24-x-yO₄₁ and Ba_1.5Sr_1.5Co_2-zY_zMn_xNi_yFe_24-x-yO₄₁ (x = y = 0.0, 0.25, 0.50, 0.75, z = 0.0, 0.05, 0.10, 0.15) were fabricated through a sol-gel auto-combustion mechanism. Analysis of dielectric and electrical properties of both compositions was undertaken. The dc electrical resistivity of Ba-Sr hexaferrites decreased from 7.09 to 2.41 (×10⁷) Ω-cm as a function of Ho-Mn-Ni doping. A similar trend is followed by Y-Mn-Ni substituted samples with lesser values for each electrical parameter. Both the compositions’ activation energy was studied using the dc electrical resistivity data. The ambient temperature dielectric characteristics of the prepared hexaferrites were investigated at varying frequencies between 64 Hz to 734 KHz. With increasing frequency, it was found that both the values of loss tangent (tanδ) and the real part of permittivity (ε′) decreased. The ac conductivity (σ_ac) remained relatively constant at the lower frequencies but increased at the higher frequencies, especially when the Ho³⁺ and Y³⁺ ions are incorporated. With these excellent electric and dielectric characteristics, the prepared compositions are highly applicable for high-frequency and antenna miniaturization usages. Graphical Abstract: (Figure presented.)