Ion Irradiation

Effect of swift heavy ion irradiation (SHI) on structural and magnetic properties of nanocrystalline spinel ferrites

This research project investigated the effects of swift heavy ion (SHI) irradiation on ferrimagnetic materials, performed at the School of Physics, Devi Ahilya Vishwa Vidyalaya, Indore, India, and funded by the Inter-University Accelerator Center, New Delhi.

Research Objectives

The primary goal was to understand how high-energy ion bombardment modifies the structural and magnetic properties of nanocrystalline spinel ferrites, with implications for radiation-hardened magnetic memory devices and spintronic applications.

Methodology

Using sol-gel auto-combustion synthesis, I prepared NiFe₂O₄ and Ni₀.₅Zn₀.₅Fe₂O₄ samples and irradiated them with 120 MeV ²⁸Si⁹⁺ ions at a fluence of 1×10¹² ions/cm². The characterization involved:

  • Structural Analysis: X-ray diffraction (XRD) to probe phase purity and lattice parameters
  • Surface Morphology: Field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray analysis (EDAX) for particle distribution and elemental composition
  • Magnetic Properties: Vibrating sample magnetometry (VSM) to measure saturation magnetization and coercivity changes

Key Outcomes

The irradiation induced significant structural modifications, including the formation of secondary phases (α-Fe₂O₃ and Ni) in pristine and irradiated Ni ferrite. Incorporation of diamagnetic Zn²⁺ ions increased the oxygen positional parameter and saturation magnetization while reducing grain size and coercivity. Post-irradiation, samples exhibited enhanced saturation magnetization with minimal coercivity changes, suggesting ion-beam engineering as a viable route for tailoring magnetic properties.

Publications & Impact

This work resulted in a conference proceeding published in AIP Conference Proceedings (2018), providing foundational insights into radiation effects on magnetic oxides. The project enhanced my expertise in magnetism fundamentals and experimental techniques, establishing the groundwork for my subsequent Ph.D. research on magnetic materials.

Skills Demonstrated

Sol-gel synthesis, ion beam irradiation, XRD, FE-SEM, EDAX, VSM, magnetic data analysis, antistructure modeling