PNNL

Abstract

Amorphous TbFeCo and TbSmFeCo thin films sputter deposited at room temperature on thermally oxidized Si substrates 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. Self 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 to induce self exchange bias and magneto-resistance switching using amorphous ferrimagnetic monolayers that require no epitaxial growth.