Modifications in ferromagnetic properties of MnAl bilayer thin films induced by swift heavy ion irradiation

In this paper, we report the effects of swift heavy ion (SHI) irradiation on structural, microstructural, and magnetic properties of Mn/Al bilayer thin films deposited by the evaporation technique. The as-deposited thin films were irradiated by a 100 MeV Ag ion beam with different fluences (1 × 10¹³–1 × 10¹⁴ ions/cm²). The enhanced ferromagnetic properties with perpendicular magnetic anisotropy have been achieved in the irradiated films with the increase in irradiation fluence, which were supported by the GIXRD, VSM, and MOKE results. The AFM study suggests that the average grain size was obtained in the range of 32–67 nm for all the films. The present study demonstrates that SHI irradiation improves the ferromagnetic properties of Mn/Al bilayer thin film, which makes it a promising material for rare-earth-free permanent magnets and spintronic applications. Graphical abstract: The graphical abstract shows the schematic diagrams of (a) the crystal structure of τ-MnAl alloy; (b) the as-deposited Mn/Al bilayer thin film on a Si substrate; (c) polar and longitudinal MOKE configuration with orientation of magnetization (M), direction of incidence (i) and reflection (r) of light. [Figure not available: see fulltext.].