Chen Dong, Wang Chun-Lei
College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China.
Phys Chem Chem Phys. 2021 Mar 18;23(10):6154-6161. doi: 10.1039/d0cp05961g.
Exploring the manipulation of magnetism in perovskite oxides is scientifically interesting and of great technical importance in next-generation magnetic memory. Dual control of magnetism in superlattices through epitaxial strain and ferroelectric polarization may induce rich physical properties. In this work, we demonstrated a strong magnetoelectric coupling that appears in an La0.75Sr0.25MnO3/BaTiO3 superlattice. Reversible transitions in ferromagnetism, ferrimagnetism and anti-ferromagnetism, with strong magnetoelectric coupling, are achieved by precisely controlling the magnitude and spin-direction of the magnetic moments of Mn. Half-metallicity is demonstrated in the MnO2 layers, accompanied by the spin polarization of the superlattice varying from 100% to 0%. We realize the coexistence of ferroelectric polarization and metallicity, i.e., "ferroelectric metal". The variation in strain and re-orientation of polarization lead to a change in interfacial Ti-O and Mn-O bond lengths, and hence a hybridization state, determining the magnetism of our system. The purpose-designed LSMO/BTO superlattice with intrinsic magnetoelectric coupling is a particularly interesting model system that can provide guidance for the development of spintronic devices.
探索钙钛矿氧化物中的磁性调控在科学上具有趣味性，并且在下一代磁存储器中具有重大技术意义。通过外延应变和铁电极化对超晶格中的磁性进行双重控制可能会诱导出丰富的物理性质。在这项工作中，我们展示了在La0.75Sr0.25MnO3/BaTiO3超晶格中出现的强磁电耦合。通过精确控制Mn磁矩的大小和自旋方向，实现了具有强磁电耦合的铁磁性、亚铁磁性和反铁磁性的可逆转变。在MnO2层中展示了半金属性，同时超晶格的自旋极化率从100%变化到0%。我们实现了铁电极化和金属性的共存，即“铁电金属”。应变的变化和极化的重新取向导致界面Ti-O和Mn-O键长的改变，进而导致杂化状态的改变，决定了我们系统的磁性。具有固有磁电耦合的目标设计LSMO/BTO超晶格是一个特别有趣的模型系统，可为自旋电子器件的发展提供指导。
