NiO Exchange Bias Layers Grown by Direct Ion Beam Sputtering of a Nickel Oxide Target

TL;DR

This paper introduces a simplified direct ion beam sputtering process for fabricating NiO exchange bias layers, enabling vacuum-sealed layered structures with comparable magnetic properties to traditional methods.

Contribution

It presents a novel IBS-based method for NiO layer deposition that simplifies fabrication and allows for full layered structure assembly without breaking vacuum.

Findings

Exchange field depends on layer thickness and temperature.

Textured single crystal and polycrystalline films show similar exchange fields.

Results align with existing theories of exchange coupling at NiO/NiFe interface.

Abstract

A new process for fabricating NiO exchange bias layers has been developed. The process involves the direct ion beam sputtering (IBS) of a NiO target. The process is simpler than other deposition techniques for producing NiO buffer layers, and facilitates the deposition of an entire spin-valve layered structure using IBS without breaking vacuum. The layer thickness and temperature dependence of the exchange field for NiO/NiFe films produced using IBS are presented and are similar to those reported for similar films deposited using reactive magnetron sputtering. The magnetic properties of highly textured exchange couples deposited on single crystal substrates are compared to those of simultaneously deposited polycrystalline films, and both show comparable exchange fields. These results are compared to current theories describing the exchange coupling at the NiO/NiFe interface.