Hassan M, Laureti S, Rinaldi C, Fagiani F, Varotto S, Barucca G, Schmidt N Y, Varvaro G, Albrecht M
Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia, nM2-Lab Via Salaria km 29.300 Monterotondo Scalo (Roma) 00015 Italy
Università Politecnica delle Marche, Dipartimento SIMAU Via Brecce Bianche Ancona 60131 Italy.
Nanoscale Adv. 2021 Apr 9;3(11):3076-3084. doi: 10.1039/d1na00110h. eCollection 2021 Jun 1.
Flexible magneto-resistive heterostructures have received a great deal of attention over the past few years as they allow for new product paradigms that are not possible with conventional rigid substrates. While the progress and development of systems with longitudinal magnetic anisotropy on non-planar substrates has been remarkable, flexible magneto-resistive heterostructures with perpendicular magnetic anisotropy (PMA) have never been studied despite the possibility to obtain additional functionality and improved performance. To fill this gap, flexible PMA Co/Pd-based giant magneto-resistive (GMR) spin-valve stacks were prepared by using an innovative transfer-and-bonding strategy exploiting the low adhesion of a gold underlayer to SiO /Si(100) substrates. The approach allows overcoming the limits of the direct deposition on commonly used polymer substrates, whose high surface roughness and low melting temperature could hinder the growth of complex heterostructures with perpendicular magnetic anisotropy. The obtained PMA flexible spin-valves show a sizeable GMR ratio (∼1.5%), which is not affected by the transfer process, and a high robustness against bending as indicated by the slight change of the magneto-resistive properties upon bending, thus allowing for their integration on curved surfaces and the development of a novel class of advanced devices based on flexible magneto-resistive structures with perpendicular magnetic anisotropy. Besides endowing the family of flexible electronics with PMA magneto-resistive heterostructures, the exploitation of the results might apply to high temperature growth processes and to the fabrication of other functional and flexible multilayer materials engineered at the nanoscale.
在过去几年中，柔性磁阻异质结构受到了广泛关注，因为它们能够实现传统刚性基板无法实现的新产品范式。虽然在非平面基板上具有纵向磁各向异性的系统取得了显著进展和发展，但具有垂直磁各向异性（PMA）的柔性磁阻异质结构尽管有可能获得额外功能和改进性能，却从未被研究过。为了填补这一空白，通过利用金底层与SiO₂/Si(100)基板之间的低附着力，采用创新的转移和键合策略制备了基于柔性PMA Co/Pd的巨磁阻（GMR）自旋阀堆栈。该方法能够克服在常用聚合物基板上直接沉积的局限性，因为聚合物基板的高表面粗糙度和低熔点温度可能会阻碍具有垂直磁各向异性的复杂异质结构的生长。所获得的PMA柔性自旋阀显示出相当大的GMR比率（约1.5%），该比率不受转移过程的影响，并且如弯曲时磁阻特性的轻微变化所示，具有高抗弯曲鲁棒性，从而允许将其集成在曲面上，并开发基于具有垂直磁各向异性的柔性磁阻结构的新型先进器件。除了为柔性电子家族赋予PMA磁阻异质结构外，利用这些结果可能适用于高温生长过程以及其他在纳米尺度设计的功能和柔性多层材料的制造。
