Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Nat Mater. 2011 Nov 13;11(1):64-8. doi: 10.1038/nmat3171.
The advent of spin transfer torque effect accommodates site-specific switching of magnetic nanostructures by current alone without magnetic field. However, the critical current density required for usual spin torque switching remains stubbornly high around 10(6)-10(7) A cm(-2). It would be fundamentally transformative if an electric field through a voltage could assist or accomplish the switching of ferromagnets. Here we report electric-field-assisted reversible switching in CoFeB/MgO/CoFeB magnetic tunnel junctions with interfacial perpendicular magnetic anisotropy, where the coercivity, the magnetic configuration and the tunnelling magnetoresistance can be manipulated by voltage pulses associated with much smaller current densities. These results represent a crucial step towards ultralow energy switching in magnetic tunnel junctions, and open a new avenue for exploring other voltage-controlled spintronic devices.
自旋转移扭矩效应的出现使得可以仅通过电流而无需磁场即可实现磁纳米结构的特定位置切换。然而，通常的自旋扭矩切换所需的临界电流密度仍然顽固地高达 10^6-10^7 A/cm^2。如果通过电压施加电场能够辅助或完成铁磁体的切换，这将从根本上具有变革性。在这里，我们报告了具有界面垂直磁各向异性的 CoFeB/MgO/CoFeB 磁性隧道结中的电场辅助可逆切换，其中矫顽力、磁构型和隧道磁阻可以通过与小得多的电流密度相关联的电压脉冲来控制。这些结果代表着在磁性隧道结中实现超低能量切换的关键一步，并为探索其他电压控制的自旋电子器件开辟了新途径。
