1] Department of Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden [2] NanOsc AB, Electrum 205, 164 40 Kista, Sweden.
Nat Commun. 2013;4:2731. doi: 10.1038/ncomms3731.
Spin-torque oscillators offer a unique combination of nanosize, ultrafast modulation rates and ultrawide band signal generation from 100 MHz to close to 100 GHz. However, their low output power and large phase noise still limit their applicability to fundamental studies of spin-transfer torque and magnetodynamic phenomena. A possible solution to both problems is the spin-wave-mediated mutual synchronization of multiple spin-torque oscillators through a shared excited ferromagnetic layer. To date, synchronization of high-frequency spin-torque oscillators has only been achieved for two nanocontacts. As fabrication using expensive top-down lithography processes is not readily available to many groups, attempts to synchronize a large number of nanocontacts have been all but abandoned. Here we present an alternative, simple and cost-effective bottom-up method to realize large ensembles of synchronized nanocontact spin-torque oscillators. We demonstrate mutual synchronization of three high-frequency nanocontact spin-torque oscillators and pairwise synchronization in devices with four and five nanocontacts.
自旋-扭矩振荡器具有独特的纳米尺寸、超快调制速率和超宽频信号生成能力，频率范围从 100MHz 到近 100GHz。然而，它们的低输出功率和大的相位噪声仍然限制了它们在自旋转移扭矩和磁动力学现象的基础研究中的应用。这两个问题的一个可能的解决方案是通过共享的被激发铁磁层，使多个自旋-扭矩振荡器通过自旋波进行相互同步。迄今为止，高频自旋-扭矩振荡器的同步仅在两个纳米触点上实现。由于昂贵的自上而下光刻工艺的制造方法对许多研究小组来说并不容易获得，因此，同步大量纳米触点的尝试几乎已经被放弃。在这里，我们提出了一种替代的、简单且具有成本效益的自下而上的方法，以实现大规模的同步纳米触点自旋-扭矩振荡器。我们演示了三个高频纳米触点自旋-扭矩振荡器的相互同步，以及在具有四个和五个纳米触点的器件中的成对同步。
