Tuning the magnetic properties of multilayered CoPt-Pt nanowires via thickness of magnetic segments

• 3D CoPt-Pt NW arrays (magnetic segments 35, 12 and 7 nm thick) are successfully fabricated by pulse electrodeposition.
• Thickness of the segments influences significantly magnetic properties of CoPt-Pt NWs.
• In CoPt-Pt NW arrays the magnetization reversal by a coherent rotation is observed.

We report on an effect of CoPt layer thickness on the magnetic properties of 3D CoPt-Pt multilayered nanowire arrays. The nanowires exhibit ferromagnetic behavior for the CoPt segments even only a few nanometers thick. It was found that decreasing thickness of CoPt nanosegments, by shortening the time of ‘magnetic material pulse’ during electrodeposition, leads to a stronger dependence of magnetization on temperature and the decrease of critical temperature. Also other magnetic parameters such as ground state magnetization, spin-wave parameter and Bloch exponent were determined for the CoPt-Pt nanowire arrays. The ground-state values of magnetization suggest that the mixing of Co and Pt occurs within the whole segment’s volume, however, the segments remain ferromagnetic. It is demonstrated that temperature dependencies of magnetization qualitatively follow the predictions of the spin-wave theory. Furthermore, based on the angle-dependent measurements of magnetization versus applied magnetic field, the coherent spin rotation was determined as a mechanism of magnetization reversal in the CoPt-Pt multilayered nanowire arrays.

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