六方锰氧化物和铁氧体中的体磁电效应。

Bulk magnetoelectricity in the hexagonal manganites and ferrites.

机构信息

School of Applied and Engineering Physics, Cornell University, 224 Clark Hall, Ithaca, New York 14853, USA.

Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA.

出版信息

Nat Commun. 2014;5:2998. doi: 10.1038/ncomms3998.

DOI:10.1038/ncomms3998

PMID:24389675

Abstract

Improper ferroelectricity (trimerization) in the hexagonal manganites RMnO3 leads to a network of coupled structural and magnetic vortices that induce domain wall magnetoelectricity and magnetization (M), neither of which, however, occurs in the bulk. Here we combine first-principles calculations, group-theoretic techniques and microscopic spin models to show how the trimerization not only induces a polarization (P) but also a bulk M and bulk magnetoelectric (ME) effect. This results in the existence of a bulk linear ME vortex structure or a bulk ME coupling such that if P reverses so does M. To measure the predicted ME vortex, we suggest RMnO3 under large magnetic field. We suggest a family of materials, the hexagonal RFeO3 ferrites, also display the predicted phenomena in their ground state.

摘要

在六方锰氧化物 RMnO3 中，铁电体（三聚体）的存在会导致结构和磁涡旋的耦合网络，从而诱导畴壁磁电效应和磁化（M），然而，这些在体相中都不会发生。在这里，我们结合第一性原理计算、群论技术和微观自旋模型，展示了三聚体不仅会诱导极化（P），还会诱导体相 M 和体相磁电（ME）效应。这导致了体相线性 ME 涡旋结构或体相 ME 耦合的存在，使得如果 P 反转，那么 M 也会反转。为了测量预测的 ME 涡旋，我们建议在强磁场下使用 RMnO3。我们还提出了一族材料，即六方 RFeO3 铁氧体，它们在基态下也表现出预测的现象。