A Study of Structural and Physical Properties of Heavily Co-doped LaSr2Mn2O7 Bi-layered Manganite
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In this paper, we report the influence of cobalt doping on the structure and magnetic properties of bilayered-perovskite LaSr2Mn2−x Co x O7 (x=0.25,0.3). Parent and doped samples were synthesized through the sol-gel method under optimized conditions. X-ray diffraction studies coupled with the Rietveld refinement of xrd data, show that both doped and parent samples crystallize in a Sr3Ti2O7-type layered perovskite structure. Temperature dependent magnetic behavior of the parent sample exhibits an antiferromagnetic and a charge-ordering state around 220 K. Magnetic field dependence of magnetization M(H) for doped samples at 20 K show well-defined M–H loops confirming the formation of intrinsic ferromagnetic ordering due to the Co doping. Additionally, we studied the ac–magnetic susceptibility and magnetization relaxation process in our samples. Dynamic scaling analysis hints an existence of glassy magnetic states in doped samples. Electrical and magnetic properties of our samples further demonstrate that Co doping suppresses charge ordering in bilayered LaSr2Mn2O7.
Keywordsbi-layered manganites Bulk Structure Properties
This research was partially funded by Brock University, Natural Sciences and Engineering Research Council of Canada (NSERC), Ministry of Research and Innovation (Ontario), and the Canada Foundation for Innovation, Canada. M.H. Ehsani thanks the Ministry of Science and Technology of Iran for the funding provided during his research in Canada.