  With the deceleration of dimensional and voltage scaling in CMOS
technologies, the demand for novel logic devices has never been greater. While
spin-based devices present a major opportunity towards favorable scaling,
switching energies are still orders of magnitude above the expected values.
Alternatively, magnetoelectric materials are predicted to enable low-power
control of magnetization, a relatively unexplored pathway with sparse results
at a device level. Here, we demonstrate voltage-based magnetization switching
and reading in nanodevices at room temperature, enabled by exchange coupling
between multiferroic BiFeO$_3$ and ferromagnetic CoFe, for the writing, and
spin-to-charge current conversion between CoFe and Pt, for the reading. Unlike
other current-based spintronic devices, magnetization writing is driven solely
by voltage pulses. We show that, upon electrical switching of the BiFeO$_3$,
the magnetization of the CoFe can be reversed, giving rise to different voltage
outputs. The voltage-induced switching is supported through a combination of
piezoresponse, magnetic force microscopy, and scanning nitrogen-vacancy
magnetometry, where magnetization reversal is linked with the polarization
state and antiferromagnetic cycloid propagation direction in the BiFeO$_3$.
This study constitutes the building block for magnetoelectric spin-orbit logic,
as well as a new avenue for low-power beyond-CMOS technologies.
