Niklas Wolff (Kiel / DE), Giovanni Masciocchi (Mainz / DE), Andriy Lotnyk (Leipzig / DE), Johannes Wilhelmus van der Jagt (Palaiseau / FR; Gif-sur-Yvette / FR), Maria-Andromachi Syskaki (Mainz / DE; Kahl am Main / DE), Alessio Lamberti (Agrate Brianza / IT), Jürgen Langer (Kahl am Main / DE), Gerhard Jakob (Mainz / DE), Benjamin Borie (Palaiseau / FR), Andreas Kehlberger (Mainz / DE), Dafine Ravelosona (Palaiseau / FR), Mathias Kläui (Mainz / DE), Lorenz Kienle (Kiel / DE)
Abstract text (incl. figure legends and references)
The control of the magnetoelastic properties of thin films is existentially relevant for the technological development of new devices which are based on the strong interaction of the material with the surrounding magnetic field. Dependent on the application, i.e. for magnetic field sensors or magnetic actuators, the magnetoelastic coefficient λs of the thin film requires dedicated tuning. One facile approach for this optimization of magnetostriction is the material combination achieved in multilayers systems [1] and to engineer the coupling properties via modification of interfaces, e.g. controlling atomic intermixing across the interfaces [2,3].
In this contribution, the progressive intermixing at the interfaces of a (2 nm 2 nm)4 Ni/Fe multilayer caused by light-ion irradiation is characterized by spectroscopic methods of probe aberration-corrected STEM, such as energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy to identify induced changes to the film"s chemical and atomic structure. Elemental mapping revealed the introduced chemical intermixing at the Ni/Fe interfaces, suggesting the formation of NixFe1-x alloys for the ion-irradiated multilayers without introducing discernible modifications to the initial crystalline structure of the stack [3]. The local chemical analyses are congruent to averaging ToF-SIMS measurements.
In conclusion, the comparison of untreated and He+-ion irradiated Ni/Fe multilayers using dedicated chemical analysis by STEM-EDX and EELS suggest that the post-growth ion-irradiation method is able of locally modifying the degree of interfacial intermixing. Thereby the saturation magnetostriction of the magnetic stack is changed and can be tuned towards the specific needs of application.
[1] Y. Nagai, M. Senda, and T. Toshima, "Properties of ion-beam-sputtered Ni/Fe artificial lattice film," Journal of Applied Physics 63, 1136–1140 (1988).
[2] J. Fassbender, D. Ravelosona, and Y. Samson, "Tailoring magnetism by light-ion irradiation," Journal of Physics D: Applied Physics 37, R179 (2004).
[3] G. Masciocchi et al. (2022), "Control of magnetoelastic coupling in Ni/Fe multilayers using He+ irradiation," ArXiV:2207.02493