  Low-energy random number generation is critical for many emerging computing
schemes proposed to complement or replace von Neumann architectures. However,
current random number generators are always associated with an energy cost that
is prohibitive for these computing schemes. In this paper, we introduce random
number bit generation based on specific nanodevices: superparamagnetic tunnel
junctions. We experimentally demonstrate high quality random bit generation
that represents orders-of-magnitude improvements in energy efficiency compared
to current solutions. We show that the random generation speed improves with
nanodevice scaling, and investigate the impact of temperature, magnetic field
and crosstalk. Finally, we show how alternative computing schemes can be
implemented using superparamagentic tunnel junctions as random number
generators. These results open the way for fabricating efficient hardware
computing devices leveraging stochasticity, and highlight a novel use for
emerging nanodevices.
