50 MeV, Lisup3+sup ion induced modifications in Mssbauer signature and hyperfine interaction parameters of Ysub3+xsubFesub5-xsubOsub12sub system

Abstract

The consequences of swift heavy ion (SHI) irradiation (Li 3+ , 50 MeV, fluence = 5  10 13 ions/cm 2 ) on the Mössbauer signature and nuclear hyperfine interaction parameters of polycrystalline Y 3+x Fe 5-x O 12 ; x = 0.0, 0.2, 0.4 and 0.6 garnet system have been studied by means of 57 Fe Mossbauer spectroscopy at 300 K. It is found that the formation of yttrium orthoferrite (YFeO 3 ) phase for higher Y 3+ -concentration compositions can effectively be reversed by swift heavy ion irradiation. Mössbauer spectral analysis reveals the formation of central enhancement in the irradiated samples that indicates the formation of localized paramagnetic centers. Hyperfine parameters analysis throws light on the presence of two magnetic phases corresponding to the ferrimagnetic garnet phase and week ferromagnetic YFeO 3 phase. The hyperfine interaction parameters of both the phases are highly influenced by SHII indicating a redistribution of cations and SHI induced formation of paramagnetic centers in the material.