  Emerging non-volatile memories (NVMs) have currently attracted great interest
for their potential applications in advanced low-power information storage and
processing technologies. Conventional NVMs, such as magnetic random access
memory (MRAM) and resistive random access memory (RRAM) suffer from limitations
of low tunnel magnetoresistance (TMR), low access speed or finite endurance.
NVMs with synergetic advantages are still highly desired for future computer
architectures. Here, we report a heterogeneous memristive device composed of a
magnetic tunnel junction (MTJ) nanopillar surrounded by resistive silicon
switches, named resistively enhanced MTJ (Re-MTJ), that may be utilized for
novel memristive memories, enabling new functionalities that are inaccessible
for conventional NVMs. The Re-MTJ device features a high ON/OFF ratio of >1000%
and multilevel resistance behaviour by combining magnetic switching together
with resistive switching mechanisms. The magnetic switching originates from the
MTJ, while the resistive switching is induced by a point-switching filament
process that is related to the mobile oxygen ions. Microscopic evidence of
silicon aggregated as nanocrystals along the edges of the nanopillars verifies
the synergetic mechanism of the heterogeneous memristive device. This device
may provide new possibilities for advanced memristive memory and computing
architectures, e.g., in-memory computing and neuromorphics.
