Enhanced interface perpendicular magnetic anisotropy in Ta|CoFeB|MgO using nitrogen doped Ta underlayers

TL;DR

This study demonstrates that nitrogen doping in Ta underlayers significantly enhances interface perpendicular magnetic anisotropy in Ta|CoFeB|MgO heterostructures, improving their potential for spintronic applications.

Contribution

It reveals that nitrogen doping in Ta underlayers reduces magnetic dead layer thickness and increases magnetic anisotropy, offering a new method to optimize spintronic device performance.

Findings

Magnetic dead layer thickness decreases with nitrogen doping.

Interface magnetic anisotropy increases to ~1.8 erg/cm2 with optimal nitrogen doping.

Doped Ta acts as an effective boron diffusion barrier.

Abstract

We show that the magnetic characteristics of Ta|CoFeB|MgO magnetic heterostructures are strongly influenced by doping the Ta underlayer with nitrogen. In particular, the saturation magnetization drops upon doping the Ta underlayer, suggesting that the doped underlayer acts as a boron diffusion barrier. In addition, the thickness of the magnetic dead layer decreases with increasing nitrogen doping. Surprisingly, the interface magnetic anisotropy increases to ~1.8 erg/cm2 when an optimum amount of nitrogen is introduced into the Ta underlayer. These results show that nitrogen doped Ta serves as a good underlayer for Spintronics applications including magnetic tunnel junctions and domain wall devices.