Exchange Bias and Bistable Magneto-Resistance States in Amorphous TbFeCo thin Films

TL;DR

This study demonstrates exchange bias and bistable magneto-resistance in amorphous TbFeCo thin films with nanoscale phase separation, enabling magnetic switching without epitaxial growth.

Contribution

It reveals exchange bias and bistable magneto-resistance in amorphous TbFeCo films due to nanoscale phase separation, a novel approach for magnetic switching.

Findings

Exchange bias observed near room temperature.

Bistable magneto-resistance states identified.

Nanoscale phase separation confirmed by microscopy.

Abstract

Amorphous TbFeCo thin films sputter deposited at room temperature on thermally oxidized Si substrate are found to exhibit strong perpendicular magnetic anisotropy (PMA). Atom probe tomography (APT), scanning transmission electron microscopy (STEM), and energy dispersive spectroscopy (EDS) mapping have revealed two nanoscale amorphous phases with different Tb atomic percentages distributed within the amorphous film. Exchange bias accompanied by bistable magneto-resistance states has been uncovered near room temperature by magnetization and magneto-transport measurements. The exchange anisotropy originates from the exchange interaction between the ferrimagnetic and ferromagnetic components corresponding to the two amorphous phases. This study provides a platform for exchange bias and magneto-resistance switching using single-layer amorphous ferrimagnetic thin films that require no epitaxial growth.