Robbennolt Shauna, Menéndez Enric, Quintana Alberto, Gómez Andrés, Auffret Stéphane, Baltz Vincent, Pellicer Eva, Sort Jordi
Departament de Física, Universitat Autònoma de Barcelona, E-08193, Cerdanyola del Vallès, Spain.
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, E-08193, Cerdanyola del Vallès, Barcelona, Spain.
Sci Rep. 2019 Jul 25;9(1):10804. doi: 10.1038/s41598-019-46618-6.
The magnetic properties of mesoporous cobalt ferrite films can be largely tuned by the application of an electric field using a liquid dielectric electrolyte. By applying a negative voltage, the cobalt ferrite becomes reduced, leading to an increase in saturation magnetization of 15% (M) and reduction in coercivity (H) between 5-28%, depending on the voltage applied (-10 V to -50 V). These changes are mainly non-volatile so after removal of -10 V M remains 12% higher (and H 5% smaller) than the pristine sample. All changes can then be reversed with a positive voltage to recover the initial properties even after the application of -50 V. Similar studies were done on analogous films without induced porosity and the effects were much smaller, underscoring the importance of nanoporosity in our system. The different mechanisms possibly responsible for the observed effects are discussed and we conclude that our observations are compatible with voltage-driven oxygen migration (i.e., the magneto-ionic effect).
介孔钴铁氧体薄膜的磁性可以通过使用液体介电电解质施加电场来进行很大程度的调节。通过施加负电压，钴铁氧体被还原，导致饱和磁化强度增加15%（M），矫顽力（H）降低5 - 28%，这取决于所施加的电压（-10 V至-50 V）。这些变化主要是非挥发性的，所以在去除-10 V后，M仍比原始样品高12%（H小5%）。即使在施加-50 V之后，所有变化都可以通过施加正电压来逆转，以恢复初始特性。对没有诱导孔隙率的类似薄膜进行了类似研究，其效果要小得多，这突出了纳米孔隙率在我们系统中的重要性。讨论了可能导致观察到的效应的不同机制，我们得出结论，我们的观察结果与电压驱动的氧迁移（即磁离子效应）相符。
