  Nanomagnetic implementations of Boolean logic [1,2] have garnered attention
because of their non-volatility and the potential for unprecedented
energy-efficiency. Unfortunately, the large dissipative losses that take place
when nanomagnets are switched with a magnetic field [3], or
spin-transfer-torque [4] inhibit the promised energy-efficiency. Recently,
there have been experimental reports of utilizing the Spin Hall effect for
switching magnets [5-7], and theoretical proposals for strain induced switching
of single-domain magnetostrictive nanomagnets [8-12], that might reduce the
dissipative losses significantly. Here, we demonstrate, for the first time,
that strain-induced switching of single-domain magnetostrictive nanomagnets of
lateral dimensions ~200 nm fabricated on a piezoelectric substrate can
implement a nanomagnetic Boolean NOT gate and unidirectional bit information
propagation in dipole-coupled nanomagnets chains. This portends
ultra-low-energy logic processors and mobile electronics that may be able to
operate solely by harvesting energy from the environment without ever requiring
a battery.
