Temperature-induced Domain Shrinking in Dipolar Frustrated Ising Ferromagnet

Motivated by recent experimental observations on ultrathin Fe/Cu(001) films, we performed a theoretical analysis of magnetic domain pattern evolution in 2D Dipolar Frustrated Ising Ferromagnet. Due to the competition between long-ranged dipolar interaction and nearest neighbor ferromagnetic exchange interaction, the ground state is given by a succession of saturated domains of positive and negative magnetization, which alternate in a sharp striped pattern of characteristic domain width $L_{gs}$. Close to the Curie temperature $T_C$, the Mean Field theory predicts the occurrence of a cosine modulation with a much smaller spatial period ($L(T_C$)). We found that these two limits are connected continuously in the temperature range $0\le T \le T_C$. But, as translational invariance does not hold, the interplay between thermal fluctuations and the two competing interactions gives rise to a non-trivial magnetization profile at intermediate temperatures.