Microwave and Solid State Assisted Synthesis of Lsmo: NiFe2O4 Nanocomposites and comparative study of its microstructural and magnetic properties

摘要

This project work is an appraisement of the effect of the synthesis route followed for the synthesis of LSMO: NFO composites, of different ratios. udLSMO and NFO individually have variety of applications, because of LSMO’s CMR behavior and NFO acts as soft ferrites with very low retentivity. But on varying the temperature of the LSMO the change in structure as well as change in magnetic behavior is observed. The double exchange process, which mediates electrical and magnetic transitions, depends on external factors and is highly susceptible to processing conditions and the chemical composition. Whereas NFO has its application in various daily life used equipments.udOur objectives in the present work include the microwave synthesis of LSMO: NFO composite through in-situ and solid-solid route, and to study the structural, microstructural and magnetic hysteresis loop.udIn the first part of the work relates to sample synthesis by in-situ route and its characterization. It was studied from DSC-TG that the calcine temperature of the composites is around 800-1000 oC. The SEM images show the compactness of the in-situ prepared samples and the crack propagation is mostly through the grain boundary. It was revealed that the NFO phase lies mostly around edge of the grain boundary or at the junction of grains. The particle size of NFO is much smaller than LSMO.udThe second part of my work mostly deals with the study of magnetic hysteresis loop of both in-situ route and solid route synthesized samples. It was revealed at the room temperature there is an increase in the distortion in the hysteresis loop with the increase in percentage of LSMO in the composite. This helps us to synthesize sample as per the requirement for an application.udududKeywords: LSMO (La–Sr–Mn–O) and NFO (NiFe2O4); SEM-scanning electron microscope. ud