Tunable properties of rare earth elements (Ce, Dy, Yb, La and Pr) substituted R-type hexagonal ferrites

A series of rare earth elements (RE = Ce, Dy, Yb, La and Pr) substituted Sr 0.9 RE 0.1 Mn 2 Fe 4 O 11 R-type hexagonal ferrites has been prepared by using the Sol–gel technique. The effect of RE substitution on its structural, electric polarization, dielectric and microwave absorption properties was studied. XRD patterns showed that all the prepared samples possess R-type hexagonal structure. The lattice parameters and unit cell volume varied with the substitution of RE contents. The average crystallite size, measured by Scherer formula, varied in the range of 6–15 nm for all samples. These results make this material suitable for being used in multilayer chip inductors (MLCI’s). The dielectric constant was found to decrease at high frequencies. This behavior has been explained on the basis of Maxwell–Wagner’s and Koop’s theory. An increase in AC conductivity was observed with increase in frequency. The decrease in lossy behavior with RE substitution in pure sample indicated the increase in the resistive nature of samples as observed from the electric polarization analysis. The Yb substituted sample exhibited highest value of microwave absorption − 40.5 dB at 11.4 GHz frequency among all the substituted samples.