Dielectric, magnetic and magneto-dielectric properties of (La, Co) co-doped BiFeO₃

Abstract

BLFCO [Bi1-xLaxFe1-xCoxO3 (x = 0.00, 0.01, 0.03, 0.05, 0.10)] ceramics were synthesised using sol-gel technique. The effect of Lanthanum (La) and Cobalt (Co) co-doping in BiFeO3 (BFO) on structural, electrical, magnetic and magneto-dielectric properties are systematically investigated. The phase purity and crystal structures were studied using X-ray diffraction technique. The dielectric properties [dielectric constant (?) and tangent loss (tan?)] were studied as a function of frequency and temperature for pure and co-doped BFO samples. The magnetization study reveals that the ferromagnetic (FM) properties in La and Co co-doped samples enhance with an increasing dopant concentration. The coercive field is found to increase with the doping concentration suggest a competition between the antiferromagnetic and ferromagnetic ordering. The Zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements of these samples also confirm the change in the magnetic behavior of BLFCO as doping concentration increases. ZFC and FC magnetization curves split at low temperature with sharp cusps suggest a spin-glass-like behaviour of BLFCO. The pure and co-doped samples exhibit a magneto-dielectric coupling effect. Furthermore, the anomaly near the magnetic phase transition (around the Neel temperature of BFO) implies the magneto-dielectric coupling in BLFCO samples.