The new frontier for spintronics is the realization of devices in which the spin can be controlled by electric fields. Multiferroics, materials exhibiting strong interplay between spin and orbital degrees of freedom, are candidates for the realization of such a paradigm. In this work, we study the magnetoelectric coupling in epitaxial \(\hbox {BiMnO}_3\) thin films which exhibit a large saturation magnetization. By combining X-ray absorption spectroscopy data and theoretical modeling, we demonstrate that \(\hbox {BiMnO}_3\) thin films have an improper magnetoelectric behavior, characterized by competing antiferromagnetic and ferromagnetic correlations. As a consequence, we show that in these materials the Mn-3d orbital and magnetic orders can be tuned via the ferroelectric polarization, opening perspectives for the realization of novel spintronic devices.

自旋电子学的新领域是实现可以通过电场控制自旋的设备。多重铁磁材料在自旋和轨道自由度之间表现出强大的相互作用，是实现这种范式的候选者。在这项工作中，我们研究了具有大饱和磁化强度的外延\（\ hbox {BiMnO} _3 \）薄膜中的磁电耦合。通过结合X射线吸收光谱数据和理论建模，我们证明了\（\ hbox {BiMnO} _3 \）薄膜具有不正确的磁电行为，其特征是反铁磁和铁磁相互竞争。结果，我们表明，在这些材料中，可以通过铁电极化来调节Mn-3d的轨道和磁阶，从而为实现新型自旋电子器件打开了前景。