Ferromagnetic Order in Two-Dimensional Spin Systems with Dipolar Interaction

We study the magnetism of two-dimensional (2D) ferromagnet with dipolar interactions. The spin wave approximation has been used to obtain the temperature dependence of magnetization, taking different limits. The internal energy and the magnon heat capacity are also calculated. We analyzed both cases that correspond to numerical and analytical results, respectively. The critical temperature is also estimated. The results are discussed in connection to the general result obtained for (2D) ferromagnet which predict a linear decrease of magnetization.