The distribution of oxygen at the Ni81Fe19/Ta interface

TL;DR

This study investigates oxygen distribution at Ni81Fe19/Ta interfaces, revealing oxygen bonding primarily to Fe, which influences interfacial properties and prevents intermixing, with implications for device optimization.

Contribution

It provides detailed characterization of oxygen bonding and distribution at Ni81Fe19/Ta interfaces using advanced X-ray techniques and simulations.

Findings

Oxygen mainly bonds to Fe atoms in Ni81Fe19.

Partial oxidation acts as a barrier to Ta intermixing.

Formation of TaOx reduces Ni81Fe19 surface oxidation.

Abstract

The knowledge of how oxygen atoms are distributed at a magnetic-metal / oxide, or magnetic-metal / non-magnetic-metal interface, can be an useful tool to optimize device production. Multilayered Ni81Fe19 / Ta samples consisting of 15 bilayers of 2.5 nm each, grown onto glass substrates by magnetron sputtering from Ni81Fe19 and Ta targets, have been investigated. X-ray absorption near edge structure, extended X-Ray absorption fine structure, small angle X-ray diffraction, and simulations, were used to characterize the samples. Oxygen atoms incorporated onto Ni81Fe19 films during O2 exposition are mainly bonded to Fe atoms. This partial oxidation of the Ni81Fe19 surface works as a barrier to arriving Ta atoms, preventing intermixing at the Ni81Fe19 / Ta interface. The reduction of the Ni81Fe19 surface by the formation of TaO x is observed.