  In real magnets the tendency towards ferromagnetism, promoted by exchange
coupling, is usually frustrated by dipolar interaction. As a result, the
uniformly ordered phase is replaced by modulated (multi-domain) phases,
characterized by different order parameters rather than the global
magnetization. The transitions occurring within those modulated phases and
towards the disordered phase are generally not of second-order type.
Nevertheless, strong experimental evidence indicates that a standard critical
behavior is recovered when comparatively small fields are applied that
stabilize the uniform phase. The resulting power laws are observed with respect
to a putative critical point that falls in the portion of the phase diagram
occupied by modulated phases, in line with an avoided-criticality scenario.
Here we propose a generalization of the scaling hypothesis for ferromagnets,
which explains this observation assuming that the dipolar interaction acts as a
relevant field, in the sense of renormalization group.
