Electric field-induced modification of magnetism in thin-film ferromagnets
Electric field-induced modification of magnetism in thin-film ferromagnets
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DOI：
10.1126/science.1136629
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发表时间：
2007-01-19
期刊：
影响因子：
56.9
通讯作者：
Givord, Dominique
中科院分区：
文献类型：
--
作者：
Weisheit, Martin;Faehler, Sebastian;Givord, Dominique
铁磁性金属表面的大电场预计会显著改变其电子密度。特别是，通常被认为是固定的材料常数的金属的本征磁性将受到影响。然而，这要求表面对材料的性能有很大的影响，就像超薄膜一样。我们证明了铁铂(FePT)和铁钯(FEPD)金属间化合物的磁晶各向异性在外加电场的作用下可以被可逆地改变。在2纳米厚的薄膜上电压变化为-0.6V时，FePT和FEPD的矫顽力分别为-4.5%和+1%。磁性参数的改变归因于未成对的d电子数随外加电场的变化。我们的器件结构是通用的，应该适用于其他薄膜磁性系统的表征。
A large electric field at the surface of a ferromagnetic metal is expected to appreciably change its electron density. In particular, the metal's intrinsic magnetic properties, which are commonly regarded as fixed material constants, will be affected. This requires, however, that the surface has a strong influence on the material's properties, as is the case with ultrathin films. We demonstrated that the magnetocrystalline anisotropy of ordered iron-platinum (FePt) and iron-palladium (FePd) intermetallic compounds can be reversibly modified by an applied electric field when immersed in an electrolyte. A voltage change of -0.6 volts on 2-nanometer-thick films altered the coercivity by -4.5 and +1% in FePt and FePd, respectively. The modification of the magnetic parameters was attributed to a change in the number of unpaired d electrons in response to the applied electric field. Our device structure is general and should be applicable for characterization of other thin-film magnetic systems.