# Contributions of Co and Fe orbitals to Perpendicular Magnetic Anisotropy of MgO/CoFeB Bilayers with Spin-Orbit-Torque-Related (Ta, W, IrMn, and Ti) Underlayers

## TL;DR

This study investigates how different underlayer materials influence the perpendicular magnetic anisotropy in CoFeB/MgO bilayers, revealing orbital moment suppression effects related to interfacial intermixing and material choice.

## Contribution

It provides new insights into the orbital contributions of Co and Fe to PMA in bilayers with various spin-orbit-torque-related underlayers.

## Key findings

- Interfacial intermixing suppresses Fe's perpendicular orbital moment.
- Intermixing suppresses both perpendicular and in-plane orbital moments of Co.
- Different underlayers affect the saturation magnetization and PMA strength.

## Abstract

We study the perpendicular magnetic anisotropy (PMA) of the CoFeB/MgO bilayers in contact with W, Ta, IrMn and Ti which has been suggested as the spin-orbit-torque-related underlayers. The saturation magnetization of the CoFeB depends on the underlayer materials due to formation of a dead-layer, affecting PMA strength of each film. The x-ray magnetic circular dichroism measurement reveals that the interfacial intermixing suppresses only the perpendicular orbital moment of Fe, while the intermixing simultaneously suppresses both the perpendicular and in-plane orbital moments of Co.

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Source: https://tomesphere.com/paper/1705.10064