Tokunaga Yusuke, Furukawa Nobuo, Sakai Hideaki, Taguchi Yasujiro, Arima Taka-hisa, Tokura Yoshinori
Multiferroic Project, ERATO, Japan Science and Technology Agency, Wako, Saitama 351-0198, Japan.
Nat Mater. 2009 Jul;8(7):558-62. doi: 10.1038/nmat2469. Epub 2009 Jun 7.
Controlling ferromagnetism by an external electric field has been a great challenge in materials physics, for example towards the development of low-power-consumption spintronics devices. To achieve an efficient mutual control of electricity and magnetism, the use of multiferroics--materials that show both ferroelectric and ferromagnetic/antiferromagnetic order--is one of the most promising approaches. Here, we show that GdFeO(3), one of the most orthodox perovskite oxides, is not only a weak ferromagnet but also possesses a ferroelectric ground state, in which the ferroelectric polarization is generated by the striction through the exchange interaction between the Gd and Fe spins. Furthermore, in this compound, ferroelectric polarization and magnetization are successfully controlled by magnetic and electric fields, respectively. This unprecedented mutual controllability of electricity and magnetism is attributed to the unique feature of composite domain wall clamping of the respective domain walls for electric and magnetic orders. This domain wall feature generally determines the efficiency of the mutual controllability and thus could have an important role towards the application of multiferroics to practical devices.
通过外部电场控制铁磁性一直是材料物理学中的一项重大挑战，例如对于低功耗自旋电子器件的发展而言。为了实现电与磁的有效相互控制，使用多铁性材料（即同时呈现铁电和铁磁/反铁磁有序的材料）是最有前景的方法之一。在此，我们表明，最典型的钙钛矿氧化物之一的GdFeO₃不仅是一种弱铁磁体，而且拥有铁电基态，其中铁电极化是通过Gd和Fe自旋之间的交换相互作用引起的磁致伸缩产生的。此外，在这种化合物中，铁电极化和磁化强度分别成功地由磁场和电场控制。这种前所未有的电与磁的相互可控性归因于电序和磁序各自畴壁的复合畴壁钳制的独特特性。这种畴壁特性通常决定了相互可控性的效率，因此对于多铁性材料在实际器件中的应用可能具有重要作用。
