Dielectric properties and magnetic behavior OF Gd3+ substituted M-type SrFe12O19 nanoferrites by auto combustion method using urea and citric acid mixtures as a dual fuel

Nanosized M-type hexaferrites Sr (1-x) Gd x Fe 12 O 19 ( x ​= ​0.00; 0.01< x ​< ​0.09; insteps of 0.02) have been synthesized by auto combustion method using urea and citric acid mixtures. Influences of Gd 3+ ions substitution on structural, electrical and magnetic properties of Sr 1-x Gd x Fe 12 O 19 nanoferrites were investigated by XRD, FTIR, FESEM, LCR meter and VSM techniques. The PXRD studies confirmed the formation of single phase lattice whereas as the sample with x ​= ​0.09 exhibits about 5% of secondary phase. It was found that the lattice parameter increased with increasing in Gd 3+ ion content. FTIR spectra have shown two absorption bands. The dielectric parameters were described based on the Maxwell–Wagner's two layer model. It is observed that the dielectric constant ( ε′ ), the loss tangent (tanδ), decrease whereas the AC conductivity (σ ac ) increases with increasing applied field frequency. Moreover, the vibrating sample magnetometer (VSM) analysis confirmed that M-SrHF's are hard magnetic in behavior. It was observed that the values of saturation magnetization (M S ), remanence magnetization (Mr), coercivity (H C ) and magnetic parameters of strontium ferrites decrease with the increase of the dopant Gd 3+ in strontium ferrites. In addition, Gd 3+ substituted SrFe 12 O 19 are most useful for magnetic recording media and electro-magnetic devices. • Nanostructured Sr (1-x) Gd x Fe 12 O 19 nanoferrites were prepared by auto combustion method using urea and citric acid mixtures as a dual fuel. • It is observed that the dielectric constant (ε'), loss tangent (tanδ), decrease and AC conductance (σ ac ) increases with increasing frequency. • The VSM studies are measured at RT and confirmed that hard magnetic nature of SrFe 12 O 19 with increase in Gd 3+ ion content. Super exchange interaction, single domine particle structure and noncolinear three sub-lattice model.