Improvement of room temperature electric polarization and ferrimagnetic properties of Co1.25Fe1.75O4 ferrite by heat treatment

Abstract

We report the improvement of electric and magnetic properties of the chemical routed samples of Co1.25Fe1.75O4 ferrite. Synchrotron X-ray diffraction pattern confirmed the cubic spinel structure in all samples. Raman spectroscopy provided the information of mixed-type cubic spinel structure, where Co2+ and Fe3+ ions order both in octahedral and tetrahedral sites. The thermal heat treatment has brought a systematic change in electric polarization and magnetic parameters. At a critical annealing temperature (TAN) of 800°C, the sample has shown the highest magnetic coercivity ~596Oe and relatively large squareness ~0.5. The electrical conductivity, dielectric loss and dielectric constant have decreased with increase of TAN. The dielectric constant becomes stable for TAN above 800°C. The samples annealed in the temperature range 900–1000°C have shown a good signature of ferroelectric polarization, although it is under saturation value and leakage of polarization due to conductive effect is observed. This work shows the scope of the improvement of electric polarization due to capacitive effect on increasing the annealing temperature of as-prepared Co ferrite sample.