Tailoring the magnetic properties of ordered arrays of patterned structures usually requires stringent control of their size, pitch, microstructure, and composition. Here, a fundamentally different approach to manipulate the magnetic behavior of lithographed microdisks, based on the application of electrical voltage, is demonstrated. First, highly porous iron oxide films with virtually no magnetic response (OFF state) are grown by sol–gel chemistry. Subsequently, arrays of microdisks (8 µm in diameter) are obtained combining lithography with wet chemical etching processes. Electrolyte‐gating (with an anhydrous electrolyte) is then employed to induce a tunable (i.e., “on‐demand”) ferromagnetic response in these disks (OFF–ON switching of magnetism) at room temperature. The changes in magnetic properties are attributed to magnetoelectrically‐driven oxygen ion migration, which is enhanced due to nanoporosity. This causes partial reduction of the oxide phases to metallic Fe. The effect can be considerably reversed by applying voltage of opposite polarity. These results are appealing for diverse technological applications that require the use of patterned structures with easily tunable magnetic properties, such as magnetic micro‐electro‐mechanical systems, microfluidic, and lab‐on‐a‐chip platforms for biomedical therapies and, ultimately, energy‐efficient magnetic memories or neuromorphic computing.

中文翻译：

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非铁磁性纳米多孔氧化铁微盘有序阵列中电压的磁感应导通开关

定制图案结构的有序阵列的磁性能通常需要严格控制其尺寸，间距，微结构和组成。在此，展示了一种基于电压的施加，从根本上不同的方法来控制光刻微盘的磁性能。首先，通过溶胶-凝胶化学法生长出几乎没有磁响应（OFF状态）的高多孔氧化铁膜。随后，将微影技术与湿法化学蚀刻工艺相结合，获得了直径为8 µm的微型磁盘阵列。然后，在室温下，通过电解质浇注（使用无水电解质）在这些磁盘中感应出可调谐的（即“按需”）铁磁响应（磁性的关－开切换）。磁性能的变化归因于磁电驱动的氧离子迁移，这由于纳米孔隙而增强。这导致氧化物相部分还原成金属Fe。通过施加相反极性的电压，可以大大抵消这种影响。这些结果吸引了需要使用具有易于调节的磁性的图案化结构的各种技术应用，例如磁性微机电系统，微流控和芯片实验室生物医学疗法以及最终的能量平台。高效的磁记忆或神经形态计算。