# CoFeAlB alloy with low damping and low magnetization for spin transfer torque switching

## TL;DR

This study explores how Al doping in CoFeB alloys affects magnetic properties, revealing reduced magnetization and damping in certain conditions, thus making CoFeAlB promising for spin torque switching with lower switching currents.

## Contribution

It provides new insights into the magnetic behavior of CoFeAlB alloys, especially regarding damping and magnetization, relevant for spintronic applications.

## Key findings

- CoFeAlB shows significantly lower magnetization than CoFeB.
- Damping parameter remains unaffected in amorphous CoFeAlB but is reduced in crystalline form.
- Crystallization process is similar in both alloys, with implications for switching current reduction.

## Abstract

We investigate the effect of Al doping on the magnetic properties of the alloy CoFeB. Comparative measurements of the saturation magnetization, the Gilbert damping parameter $\alpha$ and the exchange constant as a function of the annealing temperature for CoFeB and CoFeAlB thin films are presented. Our results reveal a strong reduction of the magnetization for CoFeAlB in comparison to CoFeB. If the prepared CoFeAlB films are amorphous, the damping parameter $\alpha$ is unaffected by the Al doping in comparison to the CoFeB alloy. In contrast, in the case of a crystalline CoFeAlB film, $\alpha$ is found to be reduced. Furthermore, the x-ray characterization and the evolution of the exchange constant with the annealing temperature indicate a similar crystallization process in both alloys. The data proves the suitability of CoFeAlB for spin torque switching properties where a reduction of the switching current in comparison with CoFeB is expected.