  Using a simple analytic approach, we study the universal properties of
second-order phase transition in holographic superconductor models. We explore
a general model in arbitrary dimensions in which the condensation occurs via
the St\"uckelberg spontaneous symmetry breaking mechanism. All the possible
second-order phase transitions and their universal characteristics can be
identified analytically. The relationship between the critical temperature and
charge density is generic, and the critical exponents can be greater than the
typical mean field value 1/2. In addition, the related numerical factors can
also be computed qualitatively.
