Electrical resistivity studies of Cr doped Mg nano-ferrites

Chromium doped magnesium nano ferrites with the formula MgCr_xFe_2−xO₄ (0 ≤ x ≤ 1) were prepared using the citrate-gel method. The electrical resistivity (ρ) was measured in the temperature range of 200–700 °C and was found to decrease with an increase in temperature ensuring the semiconducting nature of the prepared ferrites. The corresponding activation energies for conduction were obtained from the plot of log ρ vs. 1000/T for all of the compositions, which display two slopes of separate regions. It was found that the activation energy was higher in the paramagnetic region than in the ferromagnetic region. With an increase in Cr composition, the electrical resistivity was found to decrease.