Multiferroic and exchange bias in La0.85Sr0.15FeO3-δ perovskite nanoparticles

Multiferroic and exchange bias was observed in La0.85Sr0.15FeO3-delta nanoparticles sample which was prepared by co-precipitation method. These nanoparticles have an average size of about 18.49 nm and orthorhombic phase (Pbnm) with small impurities. The anomalous peaks of the dielectric as a function of temperature indicate that the Neel temperature at T-N = 321 K and a ferroelectric to paraelectric transition at T-C = 555 K which confirmed by differential scanning calorimetric (DSC). The dielectric response at low frequency is dominated by Debye relaxation behaviour and the resonance behaviour is dominated above 1.7 GHz. Mossbauer spectrum revealed the presence of magnetic ordering temperature (T-N) lies above room temperature (RT). Moreover, the oxygen deficient (delta = 0.038) was calculated from Mossbauer spectrum. The hysteresis loop (B-H) of the nanoparticle sample exhibits exchange bias as a result of the exchange coupling at the interface between the ferromagnetic surface with canted spins and the antiferromagnetic core of the particles.