Effectiveness of the Self-Consistent Harmonic Approximation in ferromagnets with dipolar interactions

Among the various methods for treating magnetic models, the Self-Consistent Harmonic Approximation (SCHA) has successfully described ferro and antiferromagnetism in many different scenarios. In particular, the SCHA is a valuable and easy formalism for determining transition temperatures as, for example, the Berezinskii-Kosterlitz-Thouless. The heart of the method includes thermal fluctuations through of a renormalization parameter depending on temperature. Nevertheless, most of the work has been done considering only short-range interactions, which results in an incomplete description of actual magnetic samples. Here, we generalize the SCHA to include the dipolar interaction in the thermodynamic analysis. The method is applied to analyze the well-known Europium Chalcogenides EuO and EuS. The SCHA results are in good agreement with the experimental measurements.

Automated summary

The Self-Consistent Harmonic Approximation (SCHA) is a useful method for studying magnetic models. However, most studies have only considered short-range interactions, resulting in incomplete descriptions of magnetic samples. In this work, the SCHA is generalized to include the dipolar interaction, leading to improved agreement with experimental measurements in the analysis of EuO and EuS.