Physical and electrical properties of Zr-Cu substituted strontium hexaferrite nanoparticles synthesized by co-precipitation method

The magnetic and electrical behavior of SrZrxCuxFe12-2xO19 (where x=0.0-0.8) hexaferrite nanoparticles are reported in this paper. Five samples were synthesized by the chemical co-precipitation method. SrFe12O19 is a semiconductor however doping ZrxCux at iron sites resulted in a semiconductor-metal transition at a temperature TM-S. The structural parameters of the samples were obtained by FUR, XRD, EDX, SEM and TEM analyses. The FTIR spectrum and XRD pattern of the samples showed that the synthesized materials were of a single phase. The particle size was in the range 26-37 nm as estimated by Scherrer formula, which is comparable with the values estimated from SEM (40-80 nm) and TEM (30-60 nm) analyses. AC magnetic susceptibility and DC electrical resistivity measurements were carried out in a temperature range 300-800 K. The Curie temperature (T-C) decreases on substitution of Zr-Cu. A significant increase in the room temperature resistivity is noted with the addition of Zr-Cu up to x <= 0.4. The drift mobility (mu(d)) and the activation energy (Delta E) are also calculated from electrical resistivity data. The variation of the dielectric constant (epsilon') and the dielectric loss factor (tan delta) with frequency in the range 80 Hz-1 MHz and composition of the sample is observed. (C) 2007 Elsevier B.V. All rights reserved.