Particle Size-Dependent Zero-Field Exchange Bias in LaFeO 3 Nanoparticles

The present communication deals with particle size-dependent zero-field cooled exchange effect in LaFeO3 (LFO). LFO nanoparticles were prepared by PVA-based sol-gel method. The sample was calcined at different temperatures (700, 750, and 800 ∘C) to tune the average particle size. The detailed crystal structural and their geometrical parameters were examined by means of Rietveld refinement using x-ray diffraction data. The different techniques such as Scherrer’s method, Williamson Hall method, FESEM, and TEM were applied to accurately determine the average particle size. Zero-field cooled exchange bias and weak ferromagnetism in antiferromagnetic nanoparticles was observed for all samples using hysteresis loop measurement. The training effect was studied to confirm that the loop shift originates due to exchange bias. Exchange bias as well as coercivity are strongly related to the particle size at low and room temperature. The results clearly demonstrate that the process of calcination tailor the overall properties of material which makes it a promising candidate for device applications.