Investigation on the suitability of IrMn based Antiferromagnetic structures for tunnelling anisotropic magnetoresistance (TAMR) applications

TAMR results from the change in the energy of states near the Fermi level in a thin metallic AFM film, due to rotation of the Néel vector with respect to the crystal lattice, leading to a change in magnetoresistance through the MgO tunnel barrier. The achievement of room temperature TAMR has important industrial potential, particularly for data storage applications.

If successful, it would allow for the creation of a hard disk drive (HDD) reader with only one FM layer, thus dramatically improving its linear resolution, and HDD areal density capacity (ADC).</div><div><br></div><div><div>The main objective of this project is to explore the suitability of Ir₂₀Mn₈₀ based structures for room temperature TAMR applications. The project has investigated numerous fabrication parameters such as seed layers, composition, deposition power and Ar flow rates which impacts the magnetic and structural properties of the structures.</div><div><br></div><div><div>Coercivity enhancement is observed from standard magnetisation measurements in very thin Ir₂₀Mn₈₀ layers (2nm) despite no corresponding exchange bias at room temperature which means the Ir₂₀Mn₈₀ layer starts to reverse with the FM layer before exchange bias is observed at 4nm.