Effect of thermal spike energy created in CuFe 2O 4 by 150 MeV Ni 11+ swift heavy ion irradiation

Abstract

Effects of 150 MeV Ni 11+ swift heavy ion (SHI) irradiation on copper ferrite nanoparticles have been studied at the fluences of 1 × 10 11, 1 × 10 12, 1 × 10 13, 1 × 10 14 and 5 × 10 14 ions/cm 2. 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 × 10 14 ions/cm 2. 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 × 10 13 ions/cm 2. At 1 × 10 14 ions/cm 2 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 × 10 13 ions/cm 2 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.