Effect of strain on magnetoresistance and magnetic properties of Co (tCo)/Ag nanostructures

A series of [Co (t_Co) nm/Ag 1.5 nm]₅₀ nanostructures was grown using pulse electrodeposition onto polyimide substrates. The magnetoresistance (MR) ratio was examined as the Co layer thickness changed. A strain was induced mechanically, and this resulted in magnetic anisotropy. Magnetization curves were recorded as the strain was changed. The measured degree of magnetic anisotropy best fits linearly with the increase of strain. The MR values for the nanostructure with the field perpendicular to the easy axis and the direction of current are found to be larger than those of the field parallel to the easy axis and the direction of current. A maximum MR ratio of 9.1 % was observed for the [Co 1.5 nm/Ag 1.5 nm]₅₀ nanostructure. The nanostructures showed remarkable magnetic properties owing to the induced strain.