Radiation induced structural and magnetic transformations in nanoparticle MnxZn(1−x)Fe2O4 ferrites

• MnxZn1−xFe2O4 nanoparticles were synthesized using auto combustion method.
• The irradiated samples showed a change in cation distribution.
• Lattice shrinkage observed due to radiation induced change in cation distribution.
• Reduction in particle size was also observed due to gamma exposure.
• An enhancement in saturation magnetization was observed in irradiated samples.

Nanoparticle magnetic materials are suitable for multiple modern high end medical applications like targeted drug delivery, gene therapy, hyperthermia and MR thermometry imaging. Majority of these applications are confined to use of Mn–Zn ferrite nanoparticles. These nanoparticles are normally left in the body after their requisite application. Preparing these nanoparticles is usually a much involved job. However with the development of the simple technique MnxZn1−xFe2O4 nanoparticles could be prepared with much ease. The nanoparticles of MnxZn1−xFe2O4 with (x=1.0, 0.7, 0.5, 0.3, 0.0) were prepared and irradiated with gamma radiation of various intensities ranging between 500 R to 10,000 R, after appropriate structural and magnetic characterization. Irradiated samples were investigated for structural and magnetic properties, as well as for structural stability and cation distribution.The irradiated nanoparticles exhibited structural stability with varied cation distribution and magnetic properties, dependent on gamma radiation dose. Surprisingly samples also exhibited quenching of lattice parameter and particle size. The changes introduced in the cation distribution, lattice constant, particle size and magnetic properties were found to be irreversible with time lapse and were of permanent nature exhibiting good stability even after several months. Thus the useful properties of nanoparticles could be enhanced on modifying the cation distribution inside the nanoparticles by application of gamma radiation.