Effect of \(\alpha \) -Particle Irradiation on the Magnetic Properties of Ni Nanowires

We report the effect of
\(\alpha \)
-particle irradiation on the magnetic properties of nickel (Ni) nanowires (NWs) arrays with diameter of each NW
\(\sim 100\)
nm prepared by electrodeposition using anodic alumina oxide (AAO) membranes. Different doses of
\(\alpha \)
-particles irradiation, up to
\(2\times 10^{16}\alpha \vphantom {\sum ^{R^{R}}}\)
/cm
\(^{2}\)
were used to observe the effect. Structural characterization indicates the reduction in crystallinity of Ni NWs after irradiation. Coercivity (
\(H_{c}\)
) was found to increase with
\(\alpha \)
-particle dose due to the formation of pinning centers. The magnetic easy axis changed direction from in-plane (with AAO template) to the out-of-plane due to the decrease in magnetocrystalline anisotropy by
\(\alpha \)
-particle irradiation. Furthermore, the effect of
\(\alpha \)
-particle irradiation on Ni NWs was studied by magnetic Barkhausen noise measurements.