Magnetic behaviour of nanosized zinc ferrite under heavy ion irradiation

Present investigation reports the effect of 100 MeV oxygen beam on the magnetic properties of zinc ferrite nanoparticles. The nanoparticles for this study were synthesized by using the nitrates of zinc and iron in the matrix of citric acid and by sintering the precursor at 500 and 1000 deg. C. Both these samples were irradiated by 100 MeV oxygen beam with two different fluence 1 x 1013 and 5 x 1013 ions/cm2. Besides the presence of cubic spinel phase, ZnO phase appears after the irradiation in both the samples. A decrease in average particle size was observed in the irradiated samples as estimated by X-ray diffraction pattern. The magnetization versus applied field curves show the decrease in magnetization with the fluence of the beam, which is attributed to the ZnO phase. The thermal magnetization curve for the sample ZF500 shows almost constant value of blocking temperature after irradiation whereas for ZF1000 it increases from 18 K to 32 K at a fluence of 5 x 1013 ions/cm2.