Wang H W, Li C L, Yuan S L, Wang J F, Lu C L, Liu J-M
School of Physics & Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Phys Chem Chem Phys. 2017 Feb 1;19(5):3706-3712. doi: 10.1039/c6cp06369a.
DyMnO hosts the less addressed duality of multiferroicity, owing to the Dy-Mn exchange striction and inverse Dzyaloshinskii-Moriya interaction between Mn spin pairs. Although the duality in DyMnO has been discussed earlier, there remains a question whether the Mn magnetic sublattice is necessarily multiferroic for generating the Dy-Mn exchange striction. In this work, we investigate the multiferroicity of Dy(MnFe)O (0 ≤ x ≤ 0.1) through detailed magnetic and ferroelectric characterization. It is found that Fe-doping continuously suppresses the independent Dy spin order but instead promotes the Dy-Mn(Fe) coupling. This coupling benefits the Dy-Mn(Fe) exchange striction which remarkably enhances the ferroelectric polarization at a low doping level (x ≤ 0.015), beyond which the Mn spiral spin order breaks down leading to collapse of the macroscopic polarization at x ≥ 0.05. This work discloses the crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction and thus highlights the duality of multiferroicity in DyMnO.
由于Dy-Mn交换应变以及Mn自旋对之间的反Dzyaloshinskii-Moriya相互作用，DyMnO呈现出较少被关注的多铁性二元性。尽管DyMnO中的二元性早前已被讨论过，但仍存在一个问题，即Mn磁亚晶格对于产生Dy-Mn交换应变是否必然是多铁性的。在这项工作中，我们通过详细的磁性和铁电特性研究了Dy(MnFe)O（0≤x≤0.1）的多铁性。研究发现，Fe掺杂持续抑制独立的Dy自旋序，但反而促进了Dy-Mn(Fe)耦合。这种耦合有利于Dy-Mn(Fe)交换应变，在低掺杂水平（x≤0.015）时显著增强铁电极化，超过该水平，Mn螺旋自旋序瓦解，导致在x≥0.05时宏观极化崩溃。这项工作揭示了Mn螺旋自旋序在稳定Dy-Mn交换应变中的关键作用，从而突出了DyMnO中多铁性的二元性。
