Current-induced spin–orbit torques (SOTs) enable
fast and
efficient manipulation of the magnetic state of magnetic tunnel junctions
(MTJs), making them attractive for memory, in-memory computing, and
logic applications. However, the requirement of the external magnetic
field to achieve deterministic switching in perpendicularly magnetized
SOT-MTJs limits its implementation for practical applications. Here,
we introduce a field-free switching (FFS) solution for the SOT-MTJ
device by shaping the SOT channel to create a “bend”
in the SOT current. The resulting bend in the charge current creates
a spatially nonuniform spin current, which translates into inhomogeneous
SOT on an adjacent magnetic free layer enabling deterministic switching.
We demonstrate FFS experimentally on scaled SOT-MTJs at nanosecond
time scales. This proposed scheme is scalable, material-agnostic,
and readily compatible with wafer-scale manufacturing, thus creating
a pathway for developing purely current-driven SOT systems.