Structural and magnetic properties of Nd-Mn substituted Y-type hexaferrites synthesized by microemulsion method

XRD patterns reveal the significant increase in line broadening which indicates a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. With the increasing substitution level of Nd-Mn, the average grain diameter decreases. The dielectric constant ε′ and dielectric loss factor ɛ″ are found to decrease initially with an increase in frequency and reached a constant value at higher frequency, exhibiting a frequency-independent behavior at higher frequencies. The dielectric loss tangent tanδ was found to decrease with an increase in the frequency. The Hc decreases remarkably with increasing Nd and Mn ions content. It was found that the particle size could be effectively decreased and coercivity Hc could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization.