This study reports the effects of post-growth He+ irradiation on the magneto-elastic properties of a Ni /Fe multi-layered stack. The progressive intermixing caused by He+ irradiation at the interfaces of the multilayer allows us to tune the saturation magnetostriction value with increasing He+ fluences, and even to induce a reversal of the sign of the magnetostrictive effect. Additionally, the critical fluence at which the absolute value of the magnetostriction is dramatically reduced is identified. Therefore insensitivity to strain of the magnetic stack is nearly reached, as required for many applications. All the above mentioned effects are attributed to the combination of the negative saturation magnetostriction of sputtered Ni, Fe layers and the positive magnetostriction of the NixFe1−x alloy at the intermixed interfaces, whose contribution is gradually increased with irradiation. Importantly the irradiation does not alter the layers polycrystalline structure, confirming that post-growth He+ ion irradiation is an excellent tool to tune the magneto-elastic properties of magnetic samples. A new class of spintronic devices can be envisioned with a material treatment able to arbitrarily change the magnetostriction with ion-induced "magnetic patterning".
@article{arxiv.2207.02493,
title = {Control of magnetoelastic coupling in Ni/Fe multilayers using He$^+$ ion irradiation},
author = {Giovanni Masciocchi and Johannes Wilhelmus van der Jagt and Maria-Andromachi Syskaki and Alessio Lamperti and Niklas Wolff and Andriy Lotnyk and Jürgen Langer and Lorenz Kienle and Gerhard Jakob and Benjamin Borie and Andreas Kehlberger and Dafine Ravelosona and Mathias Kläui},
journal= {arXiv preprint arXiv:2207.02493},
year = {2022}
}