Direct comparison of the magnetic properties of Gd0.7Sr0.3MnO3 nanoparticles with bulk counterparts

Abstract

A simple route to prepare Gd0.7Sro.3MnO3 nanoparticles by ultrasonication of their bulk powder materials was presented. The Gd0.7Sro.3MnO3 nanoparticles were also prepared by high energy ball milling technique. The transmission electron microscopic imaging demonstrated the formation of nanoparticles with average size varied from 20-40 nm and 100-150 nm, respectively by using ultrasonication and ball milling techniques. The bulk materials as well as nanoparticles synthesized by ultrasonication technique exhibited a paramagnetic to spin-glass transition at 35-40 K. On the contrary, nanoparticles synthesized by ball milling technique did not show any phase transition, however, an upturn of magnetization was observed at low temperature. A drastic change in the magnetic properties of ball milled Gd0.7Sro.3MnO3 nanoparticles than that of ultrasonically prepared nanoparticles and their corresponding bulk materials was observed. The degradation of the magnetic properties in ball milled nanoparticles may be associated with the contamination, amorphorization and formation of a nonmagnetic layer around the surface of the these nanoparticles. The outcome of this investigation demonstrated the potentially of ultrasonication technique as a physical route to prepare rare-earth based manganite nanoparticles.