Growth-dependent Interlayer Chiral Exchange and Field-free Switching

Yu-Hao Huang¹, Chao-Chung Huang¹, Wei-Bang Liao¹, Tian-Yue Chen¹, Chi-Feng Pai^1*

¹Materials Science and Engineering, National Taiwan University, Taipei, Taiwan

* Presenter:Chi-Feng Pai, email:cfpai@ntu.edu.tw

Interfacial Dzyaloshinskii-Moriya interaction (DMI) has long been observed in normal metal/ferromagnetic multilayers, enabling the formation of chiral domain walls, skyrmions and other 2D antisymmetric spin textures confined within a single ferromagnetic layer, while more recent works on interlayer DMI reveal new pathways in realizing novel chiral 3D spin textures between two separate layers. Here, we report on interlayer DMI between two orthogonally magnetized ferromagnetic layers (CoFeB/Co) mediated by a Pt layer, and confirm the chiral nature of the observed effective field of up to 100 Oe through asymmetric hysteresis loops under in-plane field. We highlight the importance of growth-induced in-plane symmetry breaking, resulting in a sizable interlayer DMI and a universal characteristic vector through wedge deposition of the samples. We further perform deterministic current-driven magnetization switching in the perpendicularly magnetized Co layer utilizing solely the effective field from the interlayer DMI. These results demonstrate the potential of interlayer DMI in facilitating deterministic field-free switching in spin-based memory applications.

Keywords: spintronics, spin-orbit torque, exchange interaction, Dzyaloshinskii-Moriya interaction