Cao Yiming, Deng Guochu, Beran Přemysl, Feng Zhenjie, Kang Baojuan, Zhang Jincang, Guiblin Nicolas, Dkhil Brahim, Ren Wei, Cao Shixun
Department of Physics, International Center of Quantum and Molecular Structures, and Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
Center for Magnetic Materials and Devices, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing, 655011, China.
Sci Rep. 2017 Oct 26;7(1):14079. doi: 10.1038/s41598-017-14169-3.
We report the structural, magnetoelectric (ME), magnetic and electric control of magnetic properties in CoNbO (CNO) single crystal. A detailed ME measurement reveals a nonlinear ME effect instead of a linear ME effect in CNO single crystal. By fitting the magnetization-electric field (M-E) curve, it can be found that the linear ([Formula: see text]) and quadratic (γ) coefficients equal to ~8.27 ps/m and ~-6.46 ps/MV for upper branch, as well as ~8.38 ps/m and ~6.75 ps/MV for the lower branch. More importantly, a pronounced response was observed under a small cooling magnetic field, which cannot even cause the spin flop. This suggests a magnetoelectric effect can occur at paraelectric state for CNO single crystal. Furthermore, we also found that the magnetization of every axis responds to electric field applied along a-axis, but fails to do so when the electric field is applied c-axis. Such findings supply a direct evidence to the magnetic structure and ME coupling mechanism indirectly reflected by our neutron experiment.
我们报道了钴铌氧化物（CNO）单晶的结构、磁电（ME）、磁性以及磁性的电控制。详细的磁电测量揭示了CNO单晶中存在非线性磁电效应而非线性磁电效应。通过拟合磁化强度 - 电场（M - E）曲线，可以发现上分支的线性（[公式：见文本]）系数和二次（γ）系数分别约为8.27 ps/m和 - 6.46 ps/MV，下分支的分别约为8.38 ps/m和6.75 ps/MV。更重要的是，在一个小的冷却磁场下观察到了明显的响应，该磁场甚至不会导致自旋翻转。这表明CNO单晶在顺电状态下可能发生磁电效应。此外，我们还发现每个轴的磁化强度对沿a轴施加的电场有响应，但当电场沿c轴施加时则没有响应。这些发现为我们的中子实验间接反映的磁结构和磁电耦合机制提供了直接证据。
