Wang P S, Ren W, Bellaiche L, Xiang H J
Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China.
Department of Physics, and International Center of Quantum and Molecular Structures, Shanghai University, Shanghai 200444, People's Republic of China.
Phys Rev Lett. 2015 Apr 10;114(14):147204. doi: 10.1103/PhysRevLett.114.147204. Epub 2015 Apr 8.
Multiferroic materials, in which ferroelectric and magnetic ordering coexist, are of practical interest for the development of novel memory devices that allow for electrical writing and nondestructive magnetic readout operation. The great challenge is to create room temperature multiferroic materials with strongly coupled ferroelectric and ferromagnetic (or ferrimagnetic) orderings. BiFeO_{3} is the most heavily investigated single-phase multiferroic to date due to the coexistence of its magnetic order and ferroelectric order at room temperature. However, there is no net magnetic moment in the cycloidal (antiferromagneticlike) magnetic state of bulk BiFeO_{3}, which severely limits its realistic applications in electric field controlled memory devices. Here, we predict that LiNbO_{3}-type Zn_{2}FeOsO_{6} is a new multiferroic with properties superior to BiFeO_{3}. First, there are strong ferroelectricity and strong ferrimagnetism at room temperature in Zn_{2}FeOsO_{6}. Second, the easy plane of the spontaneous magnetization can be switched by an external electric field, evidencing the strong magnetoelectric coupling existing in this system. Our results suggest that ferrimagnetic 3d-5d LiNbO_{3}-type material may therefore be used to achieve voltage control of magnetism in future memory devices.
在多铁性材料中，铁电有序和磁有序共存，这对于开发允许电写入和无损磁读出操作的新型存储器件具有实际意义。巨大的挑战在于制造出具有强耦合铁电和铁磁（或亚铁磁）有序的室温多铁性材料。由于BiFeO₃在室温下同时存在磁有序和铁电有序，它是迄今为止研究最多的单相多铁性材料。然而，块状BiFeO₃的摆线（类反铁磁）磁态中没有净磁矩，这严重限制了其在电场控制存储器件中的实际应用。在此，我们预测LiNbO₃型的Zn₂FeOsO₆是一种性能优于BiFeO₃的新型多铁性材料。首先，Zn₂FeOsO₆在室温下具有强铁电性和强亚铁磁性。其次，自发磁化的易平面可通过外部电场切换，这证明了该系统中存在强磁电耦合。我们的结果表明，亚铁磁性的3d - 5d LiNbO₃型材料因此可用于在未来的存储器件中实现磁的电压控制。
