  This experimental study of driven intrinsic localized modes (ILMs) in an
electronic circuit lattice with saturable nonlinearity follows the theoretical
work of Hadzievski and coworkers. They proposed that a saturable nonlinearity
could introduce transition points where localized excitations in nonintegrable
lattices would move freely. In our experiments MOS capacitors provide the
saturable nonlinearity in an electric lattice. Because of the soft nonlinearity
driver locked, auto-resonance stationary ILMs are observed below the bottom of
a linear frequency band of the lattice. With decreasing driver frequency the
width of the ILM changes in a step-wise manner as does the softening of the
barrier between site-centered and bond-centered ILM locations in agreement with
theoretical expectations. However, the steps show hysteresis between up and
down frequency scans and such hysteresis inhibits the free motion of ILMs.
