Synthesis of Ultrafine SrFe12O19 Particles with High Coercivity

Ultrafine particles of SrFelzOts have been synthesized by citrate precursor technique. Solid state reactivity studies of citrate precursor lead to the formation oEfine particles of SrFe12019below 823K.Th.e size and m o r p h o l o g y o c e area measured by BETmethod for5.2nm clystallite is found to be27.45 m2fg. havingparticlesize42nm. UltrafinepaniclesofSrFe~zOlpshows interesting magnetic properties which differs from conventional particles and are measured by VSM. The intrinsic coercive force of 65000e is observed for ultrafine SrFelz019 which is close to the theoretical limit and is one of the highest value reported so-far for isotropic SrFelz019 having 16..5.nm crystallite size. The Tc value for ultrafine particles is found to be around 830K which is larger than the reported value of 7483 for hulk materials. Mossbauer spectroscopy have ben explored to study these fine particles for non-collinear spin structure predominantly at the surface compared to the core of the particle.