Eerenstein W, Wiora M, Prieto J L, Scott J F, Mathur N D
University of Cambridge, Department of Materials Science, Pembroke Street, Cambridge CB2 3QZ, UK.
Nat Mater. 2007 May;6(5):348-51. doi: 10.1038/nmat1886. Epub 2007 Apr 8.
Magnetoelectric coupling between magnetic and electrical properties presents valuable degrees of freedom for applications. The two most promising scenarios are magnetic-field sensors that could replace low-temperature superconducting quantum interference devices, and electric-write magnetic-read memory devices that combine the best of ferroelectric and magnetic random-access memory. The former scenario requires magnetically induced continuous and reversible changes in electrical polarization. These are commonly observed, but the coupling constants thus obtained are invalid for data-storage applications, where the more difficult to achieve and rarely studied magnetic response to an electric field is required. Here, we demonstrate electrically induced giant, sharp and persistent magnetic changes (up to 2.3 x 10(-7) s m(-1)) at a single epitaxial interface in ferromagnetic 40 nm La(0.67)Sr(0.33)MnO(3) films on 0.5 mm ferroelectric BaTiO(3) substrates. X-ray diffraction confirms strain coupling via ferroelastic non-180( composite function) BaTiO(3) domains. Our findings are valid over a wide range of temperatures including room temperature, and should inspire further study with single epitaxial interfaces.
磁电耦合所展现出的磁学与电学性质之间的关联，为实际应用提供了极具价值的自由度。其中最具前景的两种应用场景分别是：有望取代低温超导量子干涉器件的磁场传感器，以及融合了铁电随机存取存储器和磁随机存取存储器优点的电写磁读存储设备。前一种应用场景要求在磁场作用下实现电极化的连续且可逆变化。这种变化通常能够被观测到，但由此获得的耦合常数对于数据存储应用而言是无效的，因为在数据存储应用中，需要的是更难实现且很少被研究的电场对磁场的响应。在此，我们展示了在0.5毫米厚的铁电体钛酸钡（BaTiO₃）衬底上的40纳米厚的铁磁体镧锶锰氧化物（La(0.67)Sr(0.33)MnO₃）外延薄膜的单个外延界面处，由电场诱导产生的巨大、尖锐且持久的磁性变化（高达2.3×10⁻⁷ 秒·米⁻¹）。X射线衍射证实了通过铁弹性非180°（复合函数）钛酸钡（BaTiO₃）畴实现的应变耦合。我们的研究结果在包括室温在内的广泛温度范围内都是有效的，并且应该会激发对单个外延界面的进一步研究。
