Effect of doping of Zr-Zn binary mixtures on structural, electrical and magnetic properties of Sr-hexaferrite nanoparticles

Nanoparticles of strontium hexaferrite doped with Zr-Zn are synthesized by a chemical co-precipitation method. The crystallite sizes of 30-47 nm are small enough to obtain a suitable signal to noise ratio for application in the magnetic recording media. The temperature dependent DC resistivity of Zr-Zn doped samples shows metal-to-semiconductor transition in the temperature (T-MS) range of 388-408 K. The Curie temperature, DC resistivity and activation energy for hopping decrease but the dielectric constant, dielectric loss and drift mobility increase by enhancing Zr-Zn content. With the substitution of Zr-Zn content of x <= 0.4 the saturation magnetization, magnetic moment and remanence increase from 71 to 92 kA m(-1), 11.2-13.6 mu B and 55-59 kA m(-1), respectively, while coercivity decreases from 137 to 34 kA m(-1). With the improvement in the values of the above-mentioned parameters, the synthesized materials may be suitable for potential application in recording media. (C) 2008 Elsevier B.V. All rights reserved.