Effect of thermal spike energy created in CuFe2O4 by 150 MeV Ni11+ swift heavy ion irradiation

Effects of 150 MeV Ni11+ swift heavy ion (SHI) irradiation on copper ferrite nanoparticles have been studied at the fluences of 1 × 1011, 1 × 1012, 1 × 1013, 1 × 1014 and 5 × 1014 ions/cm2. The XRD pattern shows the irradiation fluence dependant preferential orientation. Scanning electron microscope analysis displays fine blocks of material for pristine while partial agglomeration on irradiation. Notably, a large number of holes are present at the fluence of 5 × 1014 ions/cm2. The magnetization measurements performed in these samples exposes that the coercivity and remanence magnetization value increases due to the magnetocrystalline anisotropy up to the fluence of 1 × 1013 ions/cm2. At 1 × 1014 ions/cm2 fluence, the induced thermal energy overcomes the magnetocrystalline anisotropy constant and causes a decrease in coercivity and remanence values. The saturation magnetization decreases up to the fluence of 1 × 1013 ions/cm2 and then it increases for further irradiation. The change of crystalline orientation observed from XRD, the creation of holes from SEM and the change in magnetic properties are discussed on the basis of electro-phonon coupling and it invokes the thermal spike theory.

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► Crystalline orientation changes from [3 1 1] to [2 2 2] direction due to irradiation.
► At higher fluence the dissociation of CuFe2O4 happens.
► At the higher influence of 5 × 1014 ions/cm2, lots of holes are produced.