Huang Yen-Lin, Nikonov Dmitri, Addiego Christopher, Chopdekar Rajesh V, Prasad Bhagwati, Zhang Lei, Chatterjee Jyotirmoy, Liu Heng-Jui, Farhan Alan, Chu Ying-Hao, Yang Mengmeng, Ramesh Maya, Qiu Zi Qiang, Huey Bryan D, Lin Chia-Ching, Gosavi Tanay, Íñiguez Jorge, Bokor Jeffrey, Pan Xiaoqing, Young Ian, Martin Lane W, Ramesh Ramamoorthy
Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.
Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA, 94720, USA.
Nat Commun. 2020 Jun 5;11(1):2836. doi: 10.1038/s41467-020-16727-2.
Magnetoelectric coupling at room temperature in multiferroic materials, such as BiFeO, is one of the leading candidates to develop low-power spintronics and emerging memory technologies. Although extensive research activity has been devoted recently to exploring the physical properties, especially focusing on ferroelectricity and antiferromagnetism in chemically modified BiFeO, a concrete understanding of the magnetoelectric coupling is yet to be fulfilled. We have discovered that La substitutions at the Bi-site lead to a progressive increase in the degeneracy of the potential energy landscape of the BiFeO system exemplified by a rotation of the polar axis away from the 〈111〉 towards the 〈112〉 discretion. This is accompanied by corresponding rotation of the antiferromagnetic axis as well, thus maintaining the right-handed vectorial relationship between ferroelectric polarization, antiferromagnetic vector and the Dzyaloshinskii-Moriya vector. As a consequence, La-BiFeO films exhibit a magnetoelectric coupling that is distinctly different from the undoped BiFeO films.
室温下多铁性材料（如BiFeO）中的磁电耦合是发展低功耗自旋电子学和新兴存储技术的主要候选之一。尽管最近人们开展了广泛的研究活动来探索其物理性质，特别是关注化学改性BiFeO中的铁电性和反铁磁性，但对磁电耦合仍缺乏具体的认识。我们发现，在Bi位进行La替代会导致BiFeO系统势能面简并度逐渐增加，其表现为极轴从〈111〉向〈112〉方向旋转。这同时也伴随着反铁磁轴的相应旋转，从而保持了铁电极化、反铁磁矢量和Dzyaloshinskii-Moriya矢量之间的右手矢量关系。因此，La-BiFeO薄膜表现出与未掺杂BiFeO薄膜明显不同的磁电耦合。
