Particle size dependent structural, magnetic and electrical properties of Cr-doped lead-free multiferroic AlFeO3 prepared by co-precipitation and solid state method

Polycrystalline samples AlFe0.95Cr0.05O3 synthesized by a solid state (s) and a co-precipitation method (cop). Particle size dependent studies on structural, magnetic and dielectric properties of Cr-doped AlFeO3 have been investigated. The magnetic structure was found to be ferromagnetic. The Fe3+ ions distribution among different sites seems to be related to the preparation methods. The, saturation magnetization (Ms), remanent magnetization (Mr), are enhanced as the particle size decrease, however, coercivity (Hc) decreases. Temperature and frequency electrical impedance and modulus analysis reveal that permittivity in Cr-doped AFO is strongly dependent on microstructure and preparation condition of the samples. Two relaxation processes are detected: high-frequency grain conduction and the low-frequency grain boundary conduction. The grain boundary activation energy was estimated to be higher than that of grain, both grain and grain boundary conduction activation energies increase with decreasing particle size making AFCr5-cop samples better insulators.