Local Control of Exchange Bias by Resistive Switching (Phys. Status Solidi RRL 12/2018)

Local control of magnetism is considered as an elegant approach to optimize the performances of memory devices and magnetic logics. In article no. 1800446, Cheng Song and co-workers demonstrate the local modulation of exchange bias effect in the resistive switching structure Co/CoOx/HfOx/Pt. The cobalt-based conductive filaments and the concomitant Co metals just below the filaments at low resistive state are not pinned by the antiferromagnetic CoOx layer, leading to the absence of exchange bias, while the uniform Co film is pinned by the CoOx layer. Their combination contributes to the bi-hysteresis loops with two distinct coercivities, due to bias voltage-induced ion migration process. This finding offers a unique opportunity for controlling exchange bias locally by the formation and rupture of conductive filaments in resistive switching devices. The local control of exchange bias shows great promise for designable memories and magneto-electric coupling devices.