  We study the influence of spinless impurities on a frustrated magnet
featuring a spin-density wave (stripe) phase by means of Monte Carlo
simulations. We demonstrate that the interplay between the impurities and an
order parameter that breaks a real-space symmetry triggers the emergence of a
random-field mechanism which destroys the stripe-ordered phase. Importantly,
the strength of the emerging random fields can be tuned by the repulsion
between the impurity atoms; they vanish for perfect anticorrelations between
neighboring impurities. This provides a novel way of controlling the phase
diagram of a many-particle system. In addition, we also investigate the effects
of the impurities on the character of the phase transitions between the
stripe-ordered, ferromagnetic, and paramagnetic phases.
