Evidence of Ferromagnetic Response of TbMnO_{3} Thin Films at High Temperatures

Magnetometry measurements performed on TbMnO\(_{3}\) films grown onto single-crystal [001] SrTiO\(_{3}\) substrates using magnetron sputtering technique exhibit series of anomalies related to the magnetic ordering of the Mn\(^{3+}\) sublattice. Despite the fact that bulk TbMnO\(_{3}\) is a low-temperature antiferromagnet, the measurements indicate the presence of high-temperature ferromagnetism. Well-defined hysteresis loops are observed at temperatures as high as 70 K. Analysis of the X-ray diffraction patterns of the target and films shows no evidence of affectation (within the resolution limit of the technique) by external impurities, such as Mn\(_{3}\)O\(_{4}\), which might give rise to an artificial magnetic signal. Thus, it is probable that the ferromagnetism observed in the films to be an intrinsic property of TbMnO\(_{3}\). Concretely, it is possible that the strain imposed by the substrate, resulting in the tetragonally distorted orthorhombic phase of the TbMnO\(_{3}\) films, is behind the mechanism governing the anomalous ferromagnetism observed in the films.