Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
School of Physics and CRANN, Trinity College, Dublin 2, Ireland.
Sci Rep. 2017 Feb 2;7:42001. doi: 10.1038/srep42001.
The magnetic tunnel junction (MTJ) using MgO barrier is one of most important building blocks for spintronic devices and has been widely utilized as miniaturized magentic sensors. It could play an important role in wearable medical devices if they can be fabricated on flexible substrates. The required stringent fabrication processes to obtain high quality MgO-barrier MTJs, however, limit its integration with flexible electronics devices. In this work, we have developed a method to fabricate high-performance MgO-barrier MTJs directly onto ultrathin flexible silicon membrane with a thickness of 14 μm and then transfer-and-bond to plastic substrates. Remarkably, such flexible MTJs are fully functional, exhibiting a TMR ratio as high as 190% under bending radii as small as 5 mm. The devices' robustness is manifested by its retained excellent performance and unaltered TMR ratio after over 1000 bending cycles. The demonstrated flexible MgO-barrier MTJs opens the door to integrating high-performance spintronic devices in flexible and wearable electronics devices for a plethora of biomedical sensing applications.
基于 MgO 势垒的磁性隧道结 (MTJ) 是自旋电子器件最重要的构建模块之一，已广泛用作小型化磁传感器。如果可以在柔性衬底上制造，它将在可穿戴医疗设备中发挥重要作用。然而，获得高质量 MgO 势垒 MTJ 所需的严格制造工艺限制了其与柔性电子设备的集成。在这项工作中，我们开发了一种在厚度为 14μm 的超薄柔性硅膜上直接制造高性能 MgO 势垒 MTJ 的方法，然后将其转移并键合到塑料衬底上。值得注意的是，这种柔性 MTJ 完全功能正常，在弯曲半径小至 5mm 的情况下，TMR 比高达 190%。该器件的耐用性通过其在超过 1000 次弯曲循环后的出色性能和不变的 TMR 比得到证明。所展示的柔性 MgO 势垒 MTJ 为在柔性和可穿戴电子设备中集成高性能自旋电子器件打开了大门，可用于众多生物医学传感应用。
