Dynamic Phase Transitions in Ferromagnetic Thin Films with Different Curie Temperatures

Dynamic phase transitions (DPT) in ferromagnetic systems have recently drawn experimental and theoretical attention, mainly related to the observation of anomalous fluctuations of the order parameter that do not exist in thermal equilibrium. DPTs are characterized by changes in the period averaged magnetization Q (dynamic order parameter) as a function of a time-dependent external field H(t). Accordingly, at a critical period, the system can shift between a dynamically ordered state and a disordered one and vice versa. Despite their overall success in exploring relevant dynamic behavior, so far, all experimental studies of DPTs have been limited to low T/T_c ratios only, where Tc is the Curie temperature. As a result, the impact of T/T_c onto the DPT and the general phase space behavior has not been explored, and thus experimental knowledge is still very limited to date. Therefore, here we study experimentally the dynamic magnetic behavior for a suitable series of samples that have different T/T_c ratios, to explore their role in the vicinity of the DPT by means of a magneto-optical Kerr effect based detection scheme. Our results demonstrate that the qualitative behavior and features of the dynamic phase diagram are present independent of T/T_c.