  We report on a new sensitive method to minimize excess micromotion of an ion
in a Paul trap. The ion is placed in an ultracold cloud of neutral Rb atoms in
which ionic micromotion induces atomic losses and heating. Micromotion is
minimized by applying static electric offset fields such that both loss and
heating are minimized. We achieve a compensation precision as high as the best
compensation methods to date. In contrast to these methods, our scheme is
applicable even for ions that cannot be optically probed. Furthermore, our
method avoids the formation of temporary patch charges which are a main issue
for the long-term stability of micromotion minimization.
