  We show that the stability (existence/absence) and interaction
(repulsion/attraction) of chiral solitons in monoaxial chiral magnets can be
varied by tilting the direction of magnetic field. We, thereby, elucidate that
the condensation of attractive chiral solitons causes the discontinuous phase
transition predicted by a mean field calculation. Furthermore we theoretically
demonstrate that the metastable field-polarized-state destabilizes through the
surface instability, which is equivalent to the vanishing surface barrier for
penetration of the solitons. We experimentally measure the magnetoresistance
(MR) of micrometer-sized samples in the tilted fields in demagnetization-free
configuration. We corroborate the scenario that hysteresis in MR is a sign for
existence of the solitons, through agreement between our theory and
experiments.
