Mechanism of oxygen reduction via chemical affinity in NiO/SiO2 interfaces irradiated with keV energy hydrogen and helium ions for heterostructure fabrication

Abstract

Low-energy light ion beams are an essential resource in lithography for nanopatterning magnetic materials and interfaces due to their ability to modify the structure and properties of metamaterials. Here we create ferromagnetic/non-ferromagnetic heterostructures with a controlled layer thickness and nanometer-scale precision. For this, hydrogen ion (H⁺) irradiation is used to reduce the antiferromagnetic nickel oxide (NiO) layer into ferromagnetic Ni with lower fluence than in the case of helium ion (He⁺) irradiation. Our results indicate that H⁺ chemical affinity with oxygen is the primary mechanism for efficient atom remotion, as opposed to He⁺ irradiation, where the chemical affinity for oxygen is negligible.