Structural and magnetic properties of self-assembled Sm-Co spherical aggregates |
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Authors: | P Saravanan G Venkata RamanaK Srinivasa Rao B SreedharVTP Vinod V Chandrasekaran |
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Institution: | a Defence Metallurgical Research Laboratory, Hyderabad 500058, India b Centre for Materials for Electronics Technology, Hyderabad 500051, India c Inorganic & Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500007, India d Board of Radiation and Isotope Technology, CCMB Campus, Hyderabad 500007, India |
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Abstract: | Self-assembled Sm-Co nanoparticles in the form of spherical aggregates (referred as nanospheres) with diameter ranging from 50 to 180 nm were achieved by means of polyol technique. The size distribution of the Sm-Co nanospheres can be regulated close to ∼100 nm by controlling the molar ratio of Sm:Co precursor. The spherical aggregates exhibited Sm2Co7 phase as a major constituent; while the aggregates obtained at higher Co concentration showed co-existence of Co-phase with Sm2Co7 phase. Upon annealing, the biphasic nature of nanospheres (Sm2Co7/Co) transformed into Sm2Co17 structure. By varying the Sm:Co precursor ratio from 1:5 to 1:9, the coercivity (Hc) and magnetization (Ms) values of the as-synthesized nanospheres can be tuned from 336 to 140 Oe and from 63.7 to 108 emu/g, respectively, and these values significantly improved after annealing. Maximum values of Hc (1050 Oe) at the Sm:Co molar ratio of 1:5 and Ms of 184.6 emu/g at the Sm:Co molar ratio of 1:9 were achieved in the annealed samples. |
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Keywords: | Magnetic nanoparticle Sm-Co compound Spherical aggregate Self-assembly Polyol synthesis |
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