Current-Induced Magnetic Field Free Switching in Spin Filter Tunnel Junctions

Adopting current-driven switching mechanisms in spintronic devices has effectively addressed the challenges of magnetic field-dependent switching and large device footprints (1, 2), thereby providing a high-density, fast, energy-efficient, and non-volatile memory solution for massive data handling 3–7. The Spin-Filter Tunnel Junction (SFTJ) is emerging as an alternative spintronic device for memory applications (8, 9). However, until now, SFTJ devices have been manipulated by external magnetic fields. This paper reports the current-induced switching in the SFTJ devices, where the magnetic state of the ferromagnetic insulating manganite, Sm _0.75 Sr _0.25 MnO ₃ (SSMO), serving as the spin-filter barrier, is manipulated by the current. The realization of these devices involved the growth of lattice-matched oxide heterostructures and the fabrication of nanopillar tunnel devices, achieving an unconventional magnetoresistance (MR) of approximately 200% at 5K. This work highlights the strong influence of applied current on the magnetic switching field, suggesting a current-induced inverse metamagnetic transition in the ferromagnetic insulating barrier layer. Through comprehensive analysis under various experimental conditions and supported by theoretical calculations, this study presents the first demonstration of current-induced magnetic field-free switching in SFTJ devices. This marks a significant advancement in the field of spintronics, particularly at low temperatures, for energy-efficient cryogenic memory technology applicable to quantum electronics (10, 11) and quantum computing (12, 13).