Ghosh Ayana, Trujillo Dennis P, Choi Hongchul, Nakhmanson S M, Alpay S Pamir, Zhu Jian-Xin
Department of Materials Science & Engineering and Institute of Materials Science, University of Connecticut, Storrs, CT, 06269, USA.
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Sci Rep. 2019 Jan 17;9(1):194. doi: 10.1038/s41598-018-37339-3.
While bismuth ferrite BiFeO (BFO) is a well studied multiferroic material, its electronic and magnetic properties in the presence of A-site dopants have not been explored widely. Here we report the results of a systematic study of the local electronic structure, spontaneous polarization, and magnetic properties of lanthanum (La) and strontium (Sr) doped rhombohedral bismuth ferrite within density functional theory. An enhanced ferroelectric polarization of 122.43 μC/cm is predicted in the uniformly doped BiLaFeO. We find that substitution of Sr in the A-site drives the system into a metallic state. The nature of magnetism arises mainly from the B-site Fe exhibiting a G-type antiferromagnetic ordering. Our study finds that upon dopant substitution, the local magnetic moment is decreased and its magnitude is dependent on the distance between the Fe and the dopant atom. The correlation between the local moment and the distance between the Fe and the dopant atom is discussed.
虽然铋铁氧体BiFeO₃（BFO）是一种经过充分研究的多铁性材料，但其在A位掺杂情况下的电子和磁性能尚未得到广泛探索。在此，我们报告了在密度泛函理论框架下对镧（La）和锶（Sr）掺杂的菱方铋铁氧体的局域电子结构、自发极化和磁性能进行系统研究的结果。预测在均匀掺杂的BiLaFeO₃中，铁电极化增强至122.43 μC/cm²。我们发现，在A位用Sr替代会使系统进入金属态。磁性的本质主要源于B位Fe呈现G型反铁磁有序。我们的研究发现，掺杂替代后，局域磁矩减小，其大小取决于Fe与掺杂原子之间的距离。讨论了局域磁矩与Fe和掺杂原子之间距离的相关性。
