Enhanced magnetization in morphologically and magnetically distinct BiFeO_3 and La_(0.7)Sr_(0.3)MnO_3 composites

摘要

Nanomaterials exhibit properties different from those of their bulk counterparts. The modified magnetic characteristics of manganite nanoparticles were exploited to improve magnetization in multiferroic BiFeO_3 compound. We studied the composite of two morphologically and magnetically distinct compounds BiFeO_3 (BFO) and La_(0.7)Sr_(0.3)MnO_3 (LSMO). The microcrystalline BiFeO_3 sample was prepared by solid state reaction method and the nanocrystalline La_(0.7)Sr_(0.3)MnO_3 by sol-gel method. Composites with nominal compositions (1-x)BiFeO_3-(x)La_(0.7)Sr_(0.3)MnO_3 were prepared by modified solid state reaction method. The phase purity and crystal structures were checked by using X-ray diffraction. The formation of composites with phase separated BFO and LSMO was confirmed using Raman and Fourier Transform Infrared spectroscopy studies. The composite samples showed relatively high value of magnetization with finite coercivity. This improvement in magnetic behavior is ascribed to the coexistence of multiple magnetic orderings in composite samples. We scrutinized the possibility of oxygen vacancy or Fe mixed valency formation in the samples using X-ray photoelectron spectroscopy technique.