Swift heavy ions of various energies are being used for material modification. The induced modification depends upon the kind of defects produced during interaction of ion with the target material. In the present work, irradiation of  200 MeV Ag beam induced effect on NiCe_0.04Fe_1.96O₄ is studied at two different fluences 2× 10¹² and 1× 10¹³ ions/cm². Nanoparticles of nickel ferrite and Ce doped nickel ferrite were prepared by chemical route [1]. XRD shows peaks corresponding to pure spinel structure in both NiFe₂O₄ and NiCe_0.04Fe_1.96O₄. The pristine as well as irradiated nanoparticles were characterised by HRTEM, Raman and VSM. SAD pattern of TEM  show polycrystalline nature of the particles. Raman spectra show bands corresponding to spinel structure. Position of the bands does not change after irradiation in both systems. The widths corresponding to same band in both the systems show opposite trend with fluence.VSM results show that after irradiation the magnetisation reduces from 40 to 33 emu/gm for NiFe₂O₄ and from 39 to 31 emu/gm for NiCe_0.04Fe_1.96O₄ in comparison to pristine samples.

[1] G.Dixit, J.P.Singh, R.C.Srivastava, H.M.Agrawal, R.J.Choudhary and A.Gupta, Annealing effect on the structural and magnetic properties of nickel ferrite thin films Surf. Interface Anal. 42 (2010)151-156.

Gagan Dixit*, Govind Ballabh Pant University of Agriculture & Technology, Pantnagar, Uttarakahand, India, India
Jitendra P. Singh, , 
Ramesh Srivastava, , 
Hari Agrawal, , 
K. Asokan, , 

*presenting author