Surface Morphology and Exchange Bias Anisotropy Studies in Large Area Deposited Co2FeSi/Ir50Mn50 Multi-Layers For Spintronic Applications

Abstract

Surface morphology and magnetic properties of ferromagnetic Heusler alloy Co2FeSi thin films and their multi-layers with anti-ferromagnetic Ir50Mn50, which find applications in spintronic devices were investigated. The sputtering process flow for large area deposition of thin films on 3 inch size thermally oxidized single crystal Si(100)/SiO2 substrates have been developed by optimizing the sputtering geometry and other process parameters. A uniform film composition, thickness, smooth surface, good crystallinity and magnetic properties have been achieved in the films over 3-inch size wafers. The isotropic magnetic properties such as saturation/remanent magnetizations, coercivity were achieved in Co2FeSi films deposited on 3-inch size Si(100)/SiO2 wafers with 15 nm Cr buffer layer. An exchange bias anisotropy has been established in Co2FeSi/IrMn multilayer by magnetic annealing process using in-house made magnetic annealing set up. A maximum exchange bias anisotropy field, Hex of 178 Oe and low coercivity, Hc of 85 Oe has been achieved in the Co2FeSi/IrMn multilayer stacks suitable for magnetic tunnel junctions for spintronic applications.


photographs of as-cast Co 2 FeSi alloys prepared by vacuum induction melting and 2 inch dia., 1-5 mm thick sputtering targets wire cut from the casted alloys.
… 


Variation of film thickness as a function of distance from the origin of the wafer.
… 


M-H hysteresis loops of Co 2 FeSi thin films deposited on 3 inch thermally oxidized Si (100) wafer. the measurements were carried out at different locations by dicing the wafer (5x5) mm size square samples.
… 


Angle dependent M-H hysteresis loops of Co 2 FeSi thin films with 15 nm Cr buffer layer (a) taken at (1,1) and (b) taken at (1,-7) location. only 0 and 90 deg M-H loops are shown as other deg loops are similar to these angles.
… 


+1
polar plots representing angle dependent coercivity of Co 2 FeSi thin films deposited on 3 inch size (a) Si(100)/Sio 2 wafer and (b) Si(100)/Sio 2 wafer with 15 nm Cr buffer layer.
… 

Description