Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.
Nanoscale. 2018 Aug 2;10(30):14570-14578. doi: 10.1039/c8nr03924k.
Large magnetoelectric effects are observed in as-sputtered (nanoparticulate-like) and electrochemically dealloyed (nanoporous) 200 nm thick Fe-Cu films. Application of positive voltages decreases both the saturation magnetization (MS) and coercivity (HC) of the films, while negative voltages cause the reverse effect (increase of MS and HC). The relative variations are as high as 20% for MS and beyond 100% for HC, both for the as-sputtered and dealloyed states. These changes in magnetic properties are caused by controlled and reversible electric-field-driven nanoscale phase transformations between face-centered cubic (fcc) and body-centered cubic (bcc) structures. These phase transitions are in turn due to selective redox reactions induced by the applied voltage, which can be regarded as a "magnetoionic effect." The controlled tuning of HC and MS with the moderate values of applied voltage, together with the sustainable composition of the investigated alloys (not containing noble metals, as opposed to many previous works on magnetoelectric effects in thin films), pave the way towards the implementation of magnetic and spintronic devices with enhanced energy efficiency and functionalities.
在溅射（纳米颗粒状）和电化学脱合金（纳米多孔）的 200nm 厚 Fe-Cu 薄膜中观察到了较大的磁电效应。施加正电压会降低薄膜的饱和磁化强度 (MS) 和矫顽力 (HC)，而施加负电压则会产生相反的效果（增加 MS 和 HC）。对于溅射和脱合金状态，MS 的相对变化高达 20%，HC 的相对变化超过 100%。这些磁性能的变化是由面心立方 (fcc) 和体心立方 (bcc) 结构之间受控且可逆的电场驱动的纳米级相转变引起的。这些相变是由施加的电压引起的选择性氧化还原反应引起的，可以将其视为“磁离子效应”。通过适中的外加电压来控制 HC 和 MS 的调谐，以及所研究合金的可持续组成（不包含贵金属，与许多以前关于薄膜中磁电效应的工作相反），为实现具有增强的能量效率和功能的磁性和自旋电子器件铺平了道路。
