Gubbiotti G, Zhou X, Haghshenasfard Z, Cottam M G, Adeyeye A O, Kostylev M
Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, I-06123, Perugia, Italy.
Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.
Sci Rep. 2019 Mar 15;9(1):4617. doi: 10.1038/s41598-019-40131-6.
We have studied both experimentally and theoretically the reprogrammable spin wave band structure in Permalloy(10 nm)/Cu(5 nm)/Permalloy(30 nm) nanowire arrays of width w = 280 nm and inter-wire separation in the range from 80 to 280 nm. We found that, depending on the inter-wire separation, the anti-parallel configuration, where the magnetizations of the two Permalloy layers point in opposite directions, is stabilized over specific magnetic field ranges thus enabling us to directly compare the band structure with that of the parallel alignment. We show that collective spin waves of the Bloch type propagate through the arrays with different magnonic bandwidths as a consequence of the interplay between the intra- and inter-nanowire dynamic dipolar interactions. A detailed understanding, e.g. whether they have a stationary or propagating character, is achieved by considering the phase relation (in-phase or out-of-phase) between the dynamic magnetizations in the two ferromagnetic layers and their average value. This work opens the path to magnetic field-controlled reconfigurable layered magnonic crystals that can be used for future nanoscale magnon spintronic devices.
我们通过实验和理论研究了宽度w = 280 nm且线间距在80至280 nm范围内的坡莫合金（10 nm）/铜（5 nm）/坡莫合金（30 nm）纳米线阵列中的可重编程自旋波能带结构。我们发现，根据线间距的不同，在特定磁场范围内，两个坡莫合金层的磁化方向相反的反平行配置会变得稳定，从而使我们能够直接将能带结构与平行排列的能带结构进行比较。我们表明，由于纳米线内和纳米线间动态偶极相互作用之间的相互作用，布洛赫型的集体自旋波以不同的磁振子带宽在阵列中传播。通过考虑两个铁磁层中动态磁化强度之间的相位关系（同相或异相）及其平均值，可以实现详细的理解，例如它们是具有驻波特性还是传播特性。这项工作为磁场控制的可重构层状磁振子晶体开辟了道路，这种晶体可用于未来的纳米级磁振子自旋电子器件。
